JPH0887003A - Liquid crystal display element and its production - Google Patents

Abstract

PURPOSE: To obtain a multilayered structure of liquid crystals and high polymers having a uniform layer thickness and to enable multicoloration within the plane. CONSTITUTION: Multiple layers 12 are obtd. by successively laminating materials, such as liquid crystal or/and high polymer liquid crystal layer 13 and high polymer layers 14, having viscosity. The front surface of such multiple layers 12 is provided with a lubricant and a prescribed pressure is applied thereon by pressing, etc., by which the layers are respectively formed thinner to prescribed thicknesses and, therefore, the friction force in a transverse direction generated at the time of applying the pressure is decreased by the liquid crystal layers 13 and the lubricant constituting the respective layers and the uniform laminate having the stable layer thickness is obtd. At this time, rugged parts 11a are formed on the substrate 11 of the upper side and the cell thicknesses varying according to the ruggedness of these rugged parts 11a are obtd. and, therefore, the multicoloration is made possible within the plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-brightness reflective liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a liquid crystal display element utilizing the electro-optical effect, a TN type using a nematic liquid crystal or an STN
The type has been put to practical use. These liquid crystal display elements use a liquid crystal layer as an optical shutter by using a pair of polarizing plates. In this method, since the liquid crystal layer is used as an optical shutter, an external light source such as a backlight is required, and in order to perform colorization, R (red),
A color filter in which G (green) and B (blue) are two-dimensionally changed for each picture element is required, and the resolution is lowered to represent one display with R, G, and B.

On the other hand, it is disclosed in Japanese Unexamined Patent Publication No. 4-289818 that a reflective plate is provided on a liquid crystal display element without using a back light and used as a reflection type TN or STN liquid crystal display element. However, in this liquid crystal display device,
Since the polarizing plate is used, the light is absorbed by the polarizing plate, and the light utilization efficiency is reduced.

Further, as a means for utilizing the scattering of liquid crystal without using this polarizing plate, there are a dynamic scattering (DS) effect and a phase transition (PC) effect. Recently, there has been proposed a method of electrically controlling a transparent or cloudy state by utilizing the birefringence of a liquid crystal, which does not require a polarizing plate and does not require an alignment treatment. This method basically matches the ordinary refractive index of the liquid crystal molecules with the refractive index of the support medium, displays a transparent state when the liquid crystals are aligned by applying a voltage, and aligns the liquid crystal molecules when no voltage is applied. The light scattering state due to the turbulence is displayed. Furthermore, by adding a dichroic dye to this element, when the voltage is off,
Since the liquid crystal molecules are aligned along the polymer wall, the director of the dichroic dye is randomized to give a black display.
When the voltage is turned on, the dichroic dye is weakly colored because the liquid crystal molecules are aligned in the direction perpendicular to the electrodes. As a proposed method, a liquid crystal is precipitated by forming a liquid crystal droplet in the resin by mixing the liquid crystal and a light or thermosetting resin and curing the resin, as disclosed in Japanese Patent Publication No. 61-502128. A method of causing is disclosed.

However, in these liquid crystal display elements, a clear color tone is not obtained because the dichroic dye absorbs light even when the voltage is turned on.

A liquid crystal display element that causes selective reflection by using a liquid crystal material in which a chiral agent is added to a nematic liquid crystal or a collective liquid crystal has been known for a long time, and the display quality is very excellent, but the driving voltage is several. It is as high as 10 V, and it is difficult to change the chiral pitch within the plane to form a color. A liquid crystal display device in which this mode is confined in a polymer is disclosed in JP-A-3-
It is disclosed in Japanese Patent Publication No. 209425. In this liquid crystal display element, a mixture of a liquid crystal material, a photocurable resin, a chiral agent, and a photopolymerization initiator is irradiated with ultraviolet rays to cause phase separation of a polymer material and a chiral nematic liquid crystal. This is to electrically control the colored state and the white turbid state in which selective reflection is caused. In addition, this liquid crystal display element has a high driving voltage and is difficult to put into practical use because the spiral rods of chiral nematic liquid crystal move collectively.

Further, a method of forming a multi-layered structure with a liquid crystal and a material having a refractive index different from that of the liquid crystal is disclosed in JP-A-5-13426
No. 6 publication. This method changes the refractive index of the liquid crystal due to the change in voltage, and when the refractive index is different,
The structure is similar to that of an ABABAB type so-called interference filter, and reflection in a specific wavelength range occurs. On the other hand, when the refractive indices of the liquid crystal and other materials are set to be substantially the same, the liquid crystal becomes transparent and the color of the back surface is displayed. In this liquid crystal display element, a mixture of a liquid crystal material and a photo-curable resin is injected between substrates, the intensity of light is layered from the outside into the cell, and the photo-curable resin is cured by irradiation with diffracted light to form a layered layer. However, in reality, layers having different liquid crystal droplet diameters are formed, and the layer spacing is not constant and the color purity is low.

Further, in this liquid crystal display element, it is difficult to perform clear phase separation between the liquid crystal and the polymer material, and a region where the liquid crystal and the polymer are crossed with each other is generated, and the apparent Δd of the liquid crystal material is small. And the reflectance decreases. Further, as a similar structure, Japanese Patent Application Laid-Open No. 4-178623 discloses a reflective liquid crystal display element formed by multiple thin films of liquid crystal or polymer liquid crystal material. In this liquid crystal display device, materials such as polymer, liquid crystal, and polymer liquid crystal are applied on the substrate by spin coating, so that the thickness of each layer is constant, and in order to perform color display, liquid crystal having different reflection wavelengths is used. At least three cells or more of elements were laminated, or a structure in which cells of three colors were laminated in a plane was required.

[0009]

The above-mentioned conventional liquid crystal display device has the following problems (1) to (3).

The liquid crystal layer and the region having a constant refractive index were not clearly formed, and the color purity was poor.

It has been difficult to produce multiple colors in the plane of the display element, and it has been difficult to produce colors.

According to the above method, it is difficult to form a stable layer interval between flexible substrates, and it is not possible to adapt it to, for example, a film substrate, so that it is not possible to reduce the weight and the flexibility.

Stable diffracted light is required to control the layer spacing, and an expensive device is required.

The present invention solves the above-mentioned conventional problems. It is possible to obtain a stable multilayer structure of a liquid crystal and a polymer even between flexible substrates, and the color purity is high, and in-plane multicolor An object of the present invention is to provide a liquid crystal display element that can be made into a liquid crystal display and a method for manufacturing the same.

[0015]

A liquid crystal display device according to the present invention has a structure in which a plurality of thin layers having different refractive indices are laminated without connecting the same upper and lower layers at least in a pixel region, and the plurality of thin layers are laminated. A liquid crystal display device configured to change the refractive index of a single layer or a plurality of layers by an electric field,
The plurality of thin layers having different refractive indices are composed of a liquid crystal or / and a polymer liquid crystal layer and a polymer layer, and the refractive index of the liquid crystal or / and the polymer liquid crystal layer and the polymer layer are matched by the electric field. In this way, at least two different cell thicknesses are set in the display area, and the above-mentioned object is achieved. In addition, this liquid crystal display element has at least two portions having different thin layer thicknesses in one cell (one cell: cells not joined), and the thicknesses are different. The part is present in a repeating unit.

In the liquid crystal display element of the present invention, the same upper and lower layers are not connected to each other at least in the pixel region,
A liquid crystal display device comprising a plurality of thin layers having different refractive indexes laminated, wherein a single layer or a plurality of the plurality of thin layers have a refractive index that is changed by an electric field. The thin layer of is composed of a liquid crystal or / and a polymer liquid crystal layer and a polymer layer, and is set so that the refractive index of the liquid crystal or / and the polymer liquid crystal layer and the polymer layer are matched by the electric field, and The liquid crystal or / and the polymer liquid crystal layer of which the refractive index changes by the electric field have at least two kinds of materials having different driving voltages, and thereby the above object is achieved.

Further, preferably, the material of the substrate in the liquid crystal display element of the present invention is a plastic film material. Further, preferably, the liquid crystal display element of the present invention is provided with a concavo-convex portion on the substrate, and a different cell thickness is formed according to the concavo-convex portion of the concavo-convex portion.

Further, the method of manufacturing a liquid crystal display element of the present invention comprises a thinning step of forming a plurality of thin layers having different refractive indexes by stacking at least in the pixel region the same upper and lower layers without being connected to each other. And a step of sandwiching the plurality of thin layers between a pair of substrates, wherein the thinning step comprises laminating a liquid crystal or / and a polymer liquid crystal and a polymer material. The operation of forming a thin layer by providing a lubricant on the surface of the laminate and applying a pressure is repeated to form the plurality of thin layers, thereby achieving the above object.

[0019]

In the method of manufacturing a liquid crystal display device according to claim 5 of the present invention, liquid crystal and / or polymer liquid crystal and polymer material are sequentially laminated, a lubricant is provided on the surface of the laminate, and a predetermined pressure is applied by pressing or the like. By adding a thin layer to a predetermined thickness to form multiple thin layers, the lateral direction that occurs when pressure is applied to a viscous material with the liquid crystal layers and lubricants that make up each layer The frictional force is reduced to form a uniform laminated body with a stable layer thickness, and the color purity is improved.

Further, as in claim 1, at least two different cell thicknesses are present in each picture element of the display region, or as in claim 2, the refractive index is changed by an electric field. If at least two kinds of materials having different driving voltages are present in the liquid crystal and / or the polymer liquid crystal layer, the in-plane multicoloring and the colorization can be realized. In order to make the cell thickness different, different cell thicknesses may be formed according to the unevenness of the uneven portion of the substrate, as in the fourth aspect. In this case, different cell thicknesses can be obtained at the same time during the step of thinning to a predetermined thickness by sandwiching the above-mentioned laminated body on a substrate with uneven portions and applying a predetermined pressure, so that the process is simplified and Each has a stable cell thickness.

Further, as in claim 3, even if a plastic material such as a flexible film is used,
A multilayer structure having a stable layer thickness of liquid crystal and polymer is obtained, and not only the color purity is improved, but also a thin and lightweight liquid crystal display device is obtained.

[0022]

Embodiments of the present invention will be described below. The present invention is not limited to this embodiment.

FIG. 1 is a partial sectional view of a liquid crystal display element showing an embodiment of the present invention. In FIG. 1, a transparent electrode 2 is provided on a glass substrate 1, and a transparent electrode 4 is provided on a glass substrate 3 to form substrate portions 5 and 6, respectively. The transparent electrodes 2 and 4 sides of these substrate parts 5 and 6 are made to face each other, and a polymer liquid crystal (or //
In addition, a plurality of thin multi-layers 9 in which A layers 7 made of liquid crystal) and B layers 8 made of polymer are alternately provided are sandwiched.

As described above, in the cell of the present invention, at least one of the layers having liquid crystallinity is provided between the substrate portions 5 and 6 having the transparent electrodes 2 and 4 (in the case of the present embodiment, a polymer liquid crystal is used). It has a layered structure of multiple layers 9 which is an A layer 7).
In the laminated structure of the A layer 7 and the B layer 8, when the AB layers have different refractive indices, reflection occurs only in a specific wavelength region according to the principle of the interference filter.

When a voltage is applied, the liquid crystal director of the A layer 7 which is the polymer liquid crystal layer is aligned in the direction of the electric field, and the refractive index in the A layer 7 changes. In this case, if the refractive indexes of the A layer 7 and the B layer 8 are set so that the refractive index of the B layer 8 and the refractive index of the A layer 7 that do not change with respect to the voltage match.
The reflection in the specific wavelength region described above does not occur, the liquid crystal element becomes transparent, and the color of the back surface is displayed. Although the color of the reflecting plate as the color of the back surface varies depending on taste, it is preferable that the colored state is displayed in white due to display characteristics. That is, the display mode is a mode in which a bright and high-contrast partially reflected state (colored or clouded) and a transparent state are controlled without using a polarizing plate. The liquid crystal display element 10 of the present invention is configured as described above.

The liquid crystal display device 10 of the present invention is characterized by a great feature in its manufacturing method. According to the present invention, the liquid crystal display device 10 has a multi-layered structure having a uniform and accurate layer thickness and the same upper and lower layers are not connected to each other. The overlay 9 can be manufactured.

As shown in FIG. 2, raw material films of an A layer 7 made of a polymer liquid crystal material and a B layer 8 made of a polymer material are prepared, and the A layer 7 and the B layer 8 are alternately and sequentially formed. The layers are laminated, and a lubricant is applied to the surface of the laminate at a temperature equal to or higher than the Tg point (glass transition point) of both materials, and pressed with a predetermined pressure to form a thin layer. Further, these materials are laminated, and this operation is repeated to obtain the multi-layer 9. Finally, the multilayer 9 is sandwiched between the substrate parts 5 and 6 of which at least one is transparent, and the press is performed to a desired thickness. At this time, when plastic substrates 5 ′ and 6 ′ with ITO such as flexible and flexible films are used instead of the glass substrates 1 and 3 for the substrate portions 5 and 6, a lamination technique or the like can be used. The above-mentioned pressing step may be continuously performed by roll rolling, and in this case, the liquid crystal display element can be continuously produced.

Also, when it is difficult to press only the thin layer in the above pressing method, both sides or one side can be protected with a material having a glass transition point Tg close to each other and the material and the thin layer can be pressed simultaneously. . In this case, the lubricant and liquid crystal
It reduces spreading friction during pressing and has an important function. That is, the lateral frictional force generated when a pressure is applied to a viscous material is reduced, and the multi-layer 9 having a uniform layer thickness is formed to improve the color purity.
When a liquid crystal material is used as the material of the lubricant, liquid crystal molecules also enter between the layers and finally act as a liquid crystal layer, so that the driving voltage is reduced, which is preferable.

Therefore, even when a plastic material such as a flexible film is used, a multilayer structure having a stable layer thickness of liquid crystal and polymer can be obtained, and not only the color purity is improved, but also thin and lightweight. It becomes a liquid crystal display device.

Regarding the number of layers of the multi-layer 9, the specific wavelength is reflected by the interference of the reflected light from the interface where substances having different refractive indexes are in contact with each other according to the principle of the present invention. The larger the number, the stronger the reflection intensity due to the interference of the specific wavelength, which is preferable. Specifically, the number of pairs is preferably 7 or more, more preferably 20 or more.

Further, regarding this reflection wavelength, the reflection wavelength is determined by the optical film thickness n · d (n: refractive index, d: film thickness) because the present invention uses the λ / 4 film. Has been done.

Further, regarding the cell gap, the cell gap of the device is preferably 2 to 20 μm. When the cell gap of the device is 2 μm or less, it is difficult to obtain a cell thickness accuracy, and in the method by the hot pressing of the present invention, it is difficult to apply pressure to this thickness while maintaining a uniform layer structure. Further, if it is 20 μm or more, a sufficient driving electric field for operating liquid crystal molecules (including polymer liquid crystal) cannot be obtained.

Next, colorization in the liquid crystal display device of the present invention will be described.

An element having a uniform multilayer structure over the entire surface of the element only reflects wavelengths in one region, resulting in a monochromatic display. There are the following two methods as a method of displaying multicolor in one panel with good color purity.

As shown in FIG. 3, the reflected wavelength region can be changed by changing the cell gap in the method of manufacturing the reflection type liquid crystal display device of the present invention. According to this method, it is possible to realize full color by forming regions having different reflection wavelength regions of at least three types (three primary colors of reflected light) in each picture element of the liquid crystal display element. In order to realize this cell, for example, it is preferable that the uneven portion 11a is formed on the upper stepped substrate 11 in advance, and regions having different cell thicknesses are formed after pressing or laminating. With this stepped substrate 11, multiple layers 1
2 has different thicknesses, and the A layer 13 as a polymer liquid crystal layer and the B layer 14 as a polymer layer have different thicknesses. Different cell thicknesses are formed according to the unevenness of the uneven portion 11a of the substrate 11. Thus, the multi-gap in which the distance between layers is changed for each area enables multicoloring within the plane and colorization. The uneven portion 11a may be formed on the lower substrate or the upper and lower substrates.

Since the liquid crystal layer (including polymer liquid crystal) whose refractive index changes with voltage has at least two or more different driving voltages, multicolor display can be performed with one pixel. That is, as shown in FIG.
1, the liquid crystal layer 23 and the polymer liquid crystal layer 2 between the substrates 22 having
4, the multiple layers 26 in which the polymer layers 25 are alternately provided are sandwiched, and the voltage is off. Also, FIG.
As shown in (b), at an intermediate voltage, only the liquid crystal layer 23 is aligned parallel to the electric field, and only the polymer liquid crystal layer 24 becomes a layer having a different refractive index in response to the voltage (polymer liquid crystal). The refractive index of the layer 24 matches the refractive index of the polymer layer 25), the repeating unit is substantially lengthened, and the absorption wavelength is substantially shifted to the long wavelength side. Further, as shown in FIG. 4C, when the voltage is saturated, the liquid crystal layer 23 also becomes a layer having a different refractive index in response to the voltage (the polymer liquid crystal layer 23).
Of the polymer layer 25) and the repeating unit becomes optically transparent. In this way, by stacking layers having different operating voltages, a multicolor reflective liquid crystal display element can be realized at one point in the vertical direction.

Next, selection of materials for the liquid crystal display element of the present invention will be described.

The material in the element of the present invention needs to be composed of at least two kinds of materials, and at least one of the materials needs to be a material which causes a change in refractive index with respect to voltage. As a material that can be used, a low molecular liquid crystal material, a high molecular liquid crystal material, or a high molecular material can be selected and used.

Various combinations of materials exist as shown in (Table 1) below. (Table 1) shows the case of repeating A and B types.
Various combinations such as BC type, ABABC type and ABCD type can also be used.

[0040]

[Table 1]

In the third example of the above (Table 1), the dielectric constant Δε
May have the same type, and in this case, it is preferable that the threshold voltages are different.

The polymer liquid crystal material used in the present invention is a material containing a mesogen group exhibiting liquid crystallinity in the polymer. The mesogen group is a polar group that expresses the dielectric anisotropy of liquid crystal and the like.
_{OCH 3, -F, -Cl, -OCF} 3, a benzene ring having a functional group such as -OCCl _3, cyclohexane ring, para-diphenyl ring, a phenyl cyclohexane ring, a terphenyl ring, and the like diphenyl cyclohexane ring. It is a structure in which these mesogenic groups are bonded to a polymer chain by a linking group.

The polymer material to which a mesogenic group exhibiting liquid crystallinity is bound preferably has a glass transition temperature Tg of room temperature or lower. The glass transition temperature Tg of this polymer material is
When the glass transition temperature Tg is high, the response speed becomes slow, which affects the voltage response of the liquid crystalline polymer material. Specifically, it is polysiloxane, polyacrylate, polymethacrylate, or the like.

Further, the liquid crystal is an organic mixture which exhibits a liquid crystal state at around room temperature, and nematic liquid crystal (including liquid crystal for dual frequency driving, liquid crystal with Δε <0), cholesteric liquid crystal or addition of chiral agent. The nematic liquid crystal produced is preferable in terms of characteristics. Specifically, E
Cyanobiphenyl type such as 8, E7 (Merck), ZL
I-4801-000, ZLI-4801-001, Z
F-based liquid crystals such as LI-4792 and ZLI-4427 (manufactured by Merck).

The larger the birefringence of this liquid crystal material, the more preferable it is, and the liquid crystal layer can be thinned to lower the driving voltage. Further, the refractive index of the liquid crystal material is | ((n _e or n _o) -n _p)
It is preferable that | <0.1 (n _p is the refractive index of the polymer). Outside this range, a refractive index mismatch occurs when a voltage is applied (saturation voltage), and interference light remains, degrading display quality (contrast, etc.). More preferably, n _p matches the value of n _e or n _o . Within the above range, even when the liquid crystal molecules are driven by voltage, the difference between the refractive index of the polymer and the refractive index of the liquid crystal material is small, and the interference phenomenon occurring in the multilayer structure of the liquid crystal material and the polymer material is extremely large. Less.

Further, the polymer material will be described.
The polymer material preferably has a glass transition temperature Tg of 150 ° C. or lower in view of processing conditions such as pressing.
When the glass transition temperature Tg is 150 ° C. or higher, the processing temperature becomes high, and the fluidity of the liquid crystal material, the liquid crystalline polymer material, etc. increases too much, and a precise thin film structure cannot be maintained. Specifically, polyisoprene, polybutadiene, poly-1-pentene, polydimethylsiloxane, poly-1-butene and the like.

Further, as the substrate material, glass or polymer film which is a transparent solid, and as the non-transparent solid, a substrate with a metal thin film aiming at a reflection type, a Si substrate and the like can be used.

As the plastic substrate, polyethylene terephthalate (hereinafter referred to as PET), acrylic polymer, styrene, polycarbonate or the like can be used.

Further, two kinds of these substrates may be combined to form a cell of a different kind of substrate, and two kinds of substrates having the same kind and different kinds but different in substrate thickness may be used in combination.

Next, regarding the driving method, the prepared cell is a simple matrix driving, TFT (thin film transis
It can be driven by a driving method such as active driving such as tor) and MIM (metal insulator metal), and the liquid crystal display element of the present invention is not particularly limited to this.

Each specific example of the manufacturing method in the above embodiment will be described below.

(Specific Example 1) First, in the first step, polyisoprene (A layer: refractive index 1.52: melting point 60 ° C .:
Tg-68 ° C) and a polymer liquid crystal material (layer B) described below (thickness of about 20 µm) were prepared, and liquid crystal material E7 (manufactured by E-Merck) was applied between layers in the order of ABAB to laminate 20 sets. . This laminated body is heated to 100 ° C. and the thickness is reduced to 1/10 at a time.
Slowly compressed by hot pressing. At this time, the liquid crystal material E7 also functions as a lubricant.

Next, in the second step, plastic beads having a diameter of 8 μm were scattered on the formed film, and then sandwiched between the transparent electrode substrate-coated glass coated with the liquid crystal material E7, and the above heat pressing operation was repeated. The cross section of the produced element was a laminate having a uniform layer thickness as in FIG.

The element produced in this way is 500
It was a single green color with good color purity with a peak in the vicinity of nm. Further, when a voltage was applied to the cell, the reflection decreased while changing the reflection peak wavelength. Furthermore, by installing a black plate on the back surface, it could be used as a reflective liquid crystal display device.

(Concrete Example 2) The film produced in the first step of (Concrete Example 1) has a compression rate of 1/7 and one side is peeled off, and an uneven portion 31 shown in FIG. 5 is formed on the surface. Using the substrate 33 provided with the transparent electrode 32, plastic beads of 6 μm were scattered according to the minimum cell thickness.
Then, as in the second step of (Specific Example 1), heat compression was performed.

When the liquid crystal display element thus produced was observed with a reflection microscope, the color tone changed due to the uneven portion 31 shown in FIG. 5, and when a voltage was applied to each color portion, It was observed that each cell thickness section was a different color. Therefore, this element can be used as a reflective color liquid crystal display element.

(Specific Example 3) In the second step of (Specific Example 1), an element was prepared in the same manner as in (Specific Example 1) by using a PET film (100 μm thick) with a transparent electrode instead of the glass substrate. It was possible to obtain a liquid crystal display element having the same characteristics as the above (Specific Example 1) and being flexible.

(Specific Example 4) On the polyisoprene substrate used in the first step of (Specific Example 1), a polymer liquid crystal material represented by the following structural formula (Formula 1) having the same thickness was applied, and A reflective liquid crystal display device was prepared in the same manner as in (Specific Example 1).

[0059]

Embedded image

The cross section of the element thus produced is
Similar to the device shown in FIG. 4, it was constituted by repeating three types of layers of polymer, polymer liquid crystal, and liquid crystal. When two kinds of voltages were applied to this liquid crystal display element, the absorption wavelength peak was around 65 nm from 65 nm at a low voltage (60 V).
The absorption was decreased on the higher voltage side (90 V) by shifting to near 0 nm. It is considered that this is because the driving voltage of the liquid crystal layer and that of the polymer liquid crystal layer are different, so that the interval between the repeating units is changed and the reflection wavelength of the interference light is shifted.

As described above, the liquid crystal display element of the present invention can provide a low power consumption liquid crystal display element without the need of the backlight used in the conventional transmissive liquid crystal display element. Further, by using it together with the polymer film substrate, it is possible to provide a thin and lightweight liquid crystal display device. Furthermore, since this element is bright, has high contrast, and has excellent viewing angle characteristics, it is suitable for a portable display element, a display element viewed by a plurality of people, and the like. Further, it can be used in the field where the current liquid crystal element is used. For example, it can be used for flat display devices such as personal computers, liquid crystal television visions, and portable displays (including film substrates).

[0062]

As described above, according to the present invention, it is possible to improve color purity and the like by providing a technique for uniformly producing a multilayer structure exhibiting an interference phenomenon. It is possible to easily control the interference color by changing the refractive index of a part of the layers depending on the voltage. In addition, colorization can be achieved by changing the distance of the repeating unit in the device, which is one of the factors that determine the wavelength of reflected light. By making use of such characteristics, it can be used for a liquid crystal display element or the like that requires a reflective type with low power consumption and high contrast, such as a portable information terminal device.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a liquid crystal display element showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the principle of the cell manufacturing method of FIG.

FIG. 3 is a cross-sectional view showing the principle of a colorization cell in which the cell thickness is changed.

FIG. 4 is a cross-sectional view showing the principle of a cell that achieves colorization in the thickness direction.

FIG. 5 is a cross-sectional view of a substrate used in specific example 2.

[Explanation of symbols]

 1,3 Glass substrate 2,4,21,32 Transparent electrode 5,6 Film substrate with ITO 5 ', 6' Substrate portion 7,13 A layer made of polymer liquid crystal 8,14 B layer made of polymer 9,12 , 26 Multilayer 10 Liquid crystal display element 11 Stepped substrate 11a, 31 Concavo-convex portion 22, 33 Substrate 23 Liquid crystal layer 24 Polymer liquid crystal layer 25 Polymer layer

Claims (5)

[Claims] 1. A plurality of thin layers having different refractive indexes are laminated without connecting the same upper and lower layers at least in a pixel region, and a single layer or a plurality of the plurality of thin layers has an electric field of a refractive index. A plurality of thin layers having different refractive indices are composed of a liquid crystal or / and a polymer liquid crystal layer and a polymer layer, and the liquid crystal or / and the polymer layer are controlled by the electric field. A liquid crystal display device in which the polymer liquid crystal layer and the polymer layer are set to have the same refractive index and at least two different cell thicknesses are present in the display region. 2. A plurality of thin layers having different refractive indexes are laminated without connecting the same upper and lower layers to each other in at least a pixel region, and the refractive index of a single layer or a plurality of the plurality of thin layers is an electric field. A plurality of thin layers having different refractive indices are composed of a liquid crystal or / and a polymer liquid crystal layer and a polymer layer, and the liquid crystal or / and the polymer layer are controlled by the electric field. At least two kinds of materials having different driving voltages are present in the liquid crystal or / and the polymer liquid crystal layer which are set so that the polymer liquid crystal layer and the polymer layer have the same refractive index and whose refractive index is changed by the electric field. A liquid crystal display device having a configuration. 3. A plurality of thin layers having different refractive indexes, which are laminated without connecting the same upper and lower layers at least in a pixel region, are sandwiched between a pair of substrates, and a single layer among the plurality of thin layers is sandwiched. 3. A liquid crystal display device in which the refractive index of a plurality of layers changes according to an electric field, wherein the substrate material is a plastic material.
The liquid crystal display element described. 4. A plurality of thin layers having different refractive indices, which are laminated without connecting the same upper and lower layers at least in a pixel region, are sandwiched between a pair of substrates, and a single layer among the plurality of thin layers is sandwiched. 2. A liquid crystal display element in which the refractive index of a plurality of layers changes according to an electric field, wherein uneven portions are formed on the substrate, and different cell thicknesses are formed according to the unevenness of the uneven portions. Liquid crystal display element. 5. A thinning step of forming a plurality of thin layers having different refractive indexes by stacking at least in the pixel region without connecting the same upper and lower layers to each other, and between the pair of substrates. A method of manufacturing a liquid crystal display element, the method comprising: sandwiching the liquid crystal and / or a polymer liquid crystal and a polymer material, and providing a lubricant on the surface of the laminate. A method of manufacturing a liquid crystal display element, wherein a plurality of thin layers are formed by repeating an operation of thinning by applying pressure.