JP2001056483A - Liquid crystal display element, driving method of the same and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the manufacturing stage and to reduce the manufacturing costs by simplifying the structure of an HPDLC element capable of color display. SOLUTION: This liquid crystal display element has two periodic structures 16 and 17 between a pair of transparent substrates 12 and 13 having alignment layers 14 and 15 formed on the surfaces thereof respectively. The alignment layers 14 and 15 are divided respectively into two regions corresponding to the two periodic structures, which are rubbed in an orthogonal direction to each other. Each of the two periodic structures has multi-structure consisting of liquid crystal layers and polymer layers and their periodic intervals are different from each other. Liquid crystal molecules in each liquid crystal layer are aligned in the direction parallel to the rubbing direction of the alignment layer. Reflection/transmission of light beams corresponding to two colors are controlled by impressing an electric field on this liquid crystal element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device used for a reflection type color liquid crystal display and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as the demand for portable information terminals and the like has increased, a color display which is smaller, lighter, consumes less power, and has high display quality has been required.

As a display satisfying such demands, HPDLC (Holographic Polymer Dispersed Liquor
There is a reflection type color display using an id crystal) element. Since the HPDLC element can perform color display without using a polarizing plate or a color filter, it can display with high brightness and high color purity.

A conventional HPDLC device is disclosed in
There is one described in Japanese Patent No. 294952. This HP
The DLC element is, as shown in FIG.
And two transparent substrates 112 and 113 and a transparent substrate 11
Transparent electrodes 11 formed on the surfaces of 2, 113 respectively
4, 115, and a periodic structure in which liquid crystal layers 116 and polymer layers 117 are alternately laminated between two transparent substrates 112, 113 on which transparent electrodes 114, 115 are formed, respectively. are doing.

[0005] The liquid crystal layer 116 has transparent electrodes 114 and 115.
The refractive index changes according to the voltage (electric field) applied therebetween. Utilizing this, the periodic structure is made of the transparent electrode 11.
In the state where no voltage is applied between the electrodes 4 and 115, light in a specific wavelength range is reflected and light in other wavelength ranges is transmitted by the principle of an interference filter, and the transparent electrode 11
In a state where a predetermined voltage is applied between 4, 115 and 115, light in a specific wavelength range is transmitted together with other wavelength ranges.

That is, when no voltage is applied between the transparent electrodes 114 and 115, there is a difference in the refractive index between the liquid crystal layer 116 and the polymer layer 117.
6 and the polymer layer 117 are reflected in the wavelength region corresponding to the lamination period interval. Therefore, when viewed from the surface, the HPDLC element appears to display a specific color. Further, a voltage is applied between the transparent electrodes 114 and 115 so that the liquid crystal layer 11 is
When the refractive index difference between the polymer layer 117 and the polymer layer 117 is reduced, the ratio of light of a specific wavelength reflected by the periodic structure decreases, and the luminance of a specific color displayed decreases. When the refractive index of the liquid crystal layer 116 becomes equal to the refractive index of the polymer layer 117, light in a specific wavelength band transmits through the periodic structure like other light,
Certain colors disappear.

As described above, the HPDLC element can display a specific color according to the period interval between the liquid crystal layer 116 and the polymer layer 117. Therefore, as shown in FIG. 11, a reflective liquid crystal display capable of full-color display can be realized by using three types of HPDLC elements in which lamination period intervals are set so as to correspond to blue, green, and red.

As a method of arranging three kinds (three colors) of HPDLC elements to enable full-color display, as shown in FIG. In addition to the method of arranging, as shown in FIG. 12, there is a method of laminating three kinds of HPDLC elements.

The HPDLC elements shown in FIGS. 11 and 12 employ a simple matrix system as a driving system, but use an HPDLC system employing an active matrix system.
There are also LC elements. The HPDLC element adopting such an active matrix system is disclosed in, for example,
Japanese Patent Application Laid-Open No. 9-265088,
It is also described in Japanese Patent Publication No.

[0010] The above-mentioned HPDLC element has a drawback that the driving voltage is high. Also, in the above-mentioned HPDLC, the liquid crystal material exhibits random alignment when no voltage is applied, so that the difference in the refractive index between the liquid crystal layer and the polymer layer is considerably smaller than the difference in the refractive index between the liquid crystal material and the polymer material. There is also a disadvantage that the reflectance is low.

As a display element which has solved the above-mentioned disadvantage, there is a display element described in Japanese Patent Application Laid-Open No. 10-123561. This display element is composed of a first layer of an optically anisotropic material that is alternately stacked and whose orientation can be controlled by an electric field, and an optically anisotropic material whose orientation is independent of an electric field. And a second layer. The display element is configured such that the orientation directions of the first layer and the second layer substantially match when no voltage is applied. In other words, in this display element, the liquid crystal material is oriented in a certain direction so that the refractive index difference between the major axis direction and the minor axis direction of the liquid crystal material can be used to the maximum, thereby improving the reflectance of a specific color. Let me.

[0012]

When color display is performed using the HPDLC elements, there are cases where each HPDLC element is arranged in a plane and in a case where the HPDLC elements are stacked, and in each case, the HPDLC elements of each color are independently driven. In order to be able to do so, it is necessary to provide a pair of electrodes for every HPDLC element. That is, the conventional HPDLC element has a problem that its structure is complicated.

When a conventional display using an HPDLC element is driven by an active matrix system, not only an electrode pair but also an active element such as a TFT must be provided for each HPDLC element. In addition, when the HPDLC elements of each color are stacked, a contact hole 132 for connecting the active element (TFT) 131 and the electrode 114, an insulating layer 133, and the like are required as shown in FIG. Therefore, when the conventional HPDLC element is driven by the active matrix method, not only the structure is further complicated, but also a space for providing the active element is required, and the effective area in display is reduced. is there.

The present invention relates to an HPDLC capable of color display.
It is an object of the present invention to simplify the structure of an element, simplify a manufacturing process, and reduce cost.

[0015]

The present invention comprises a plurality of periodic structures in which liquid crystal layers and polymer layers are alternately laminated, and the plurality of periodic structures are different from each other in accordance with an applied electric field. In a liquid crystal display element that reflects or transmits light in a frequency band, the orientation directions of the liquid crystal materials of the liquid crystal layers of each of the plurality of periodic structures are set to directions different from each other, and a common electric field is applied to simultaneously set the orientation directions. By controlling
The invention is characterized in that the plurality of periodic structures are driven simultaneously.

Here, in the present invention, the plurality of periodic structures constitute one pixel.

In the present invention, the plurality of periodic structures may be arranged such that each forms a domain.

In this case, if the plurality of periodic structures are arranged between a pair of transparent substrates, an alignment film is provided between the transparent substrate and the plurality of periodic structures. Is also good.

In the present invention, the plurality of periodic structures may be stacked on each other.

In this case, if the plurality of periodic structures are arranged between a pair of transparent substrates, the plurality of periodic structures are disposed between each of the transparent substrates and the periodic structure and the plurality of periodic structures. Orientation films may be provided between each other.

Further, according to the present invention, when two periodic structures are provided as the plurality of periodic structures, the alignment direction of the liquid crystal material of one periodic structure and the periodic direction of the other periodic structure are different. The alignment direction of the liquid crystal material may be made orthogonal.

Alternatively, as the plurality of periodic structures, 3
In the case of having one periodic structure, the alignment direction of the liquid crystal material of each periodic structure may be different from the alignment direction of the liquid crystal material of another periodic structure by 60 °.

In the present invention, a smectic liquid crystal can be used as the liquid crystal material, and preferably, a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or a ferrielectric liquid crystal is used.

In the present invention, the polymer layer may be
A photocurable material can be used, and a liquid crystal monomer, particularly a smectic liquid crystal monomer, is preferably used.

Further, according to the present invention, a plurality of electric fields having mutually different directions or a single electric field having a plurality of electric field vector components having mutually different directions are used to form a plurality of mutually different wavelengths. A method of driving a liquid crystal display element, characterized in that the reflectivity to light is controlled simultaneously.

According to the present invention, a mixture of a liquid crystal material and a photocurable material is sandwiched between a pair of substrates, and the mixture sandwiched between the substrates is divided into a plurality of regions. A step of orienting the liquid crystal material in specific directions different from each other for each region,
Each of the plurality of regions is irradiated with different interference light to form a plurality of multilayer structures in which a layer in which the photocurable material is polymerized and a layer in which the light-effective material is not polymerized and which becomes a liquid crystal layer are alternately stacked. And a method of manufacturing a liquid crystal display element.

Here, as the step of aligning the liquid crystal material in a specific direction, a rubbing step using an alignment film or a step of applying an electric field can be used.

In the present invention, when the plurality of regions are two regions, S-polarized light and P-polarized light can be used as the mutually different interference lights.

Further, in the present invention, mutually different interference lights can be obtained by changing the incident angle of the interference light irradiating the plurality of areas for each area.

Further, according to the present invention, a step of positioning a first mixture obtained by mixing a liquid crystal material and a photocurable material on a substrate, and the step of: transferring the liquid crystal material contained in the first mixture to the first mixture.
And a step of irradiating the first mixture with first interference light to form a layer in which the photocurable material is polymerized and a layer in which the light-effective material is not polymerized and becomes a liquid crystal layer. Forming a first multilayer structure in which the liquid crystal material and the photocurable material are mixed alternately, and positioning a second mixture of the liquid crystal material and the photocurable material on the multilayer structure substrate;
Orienting the liquid crystal material contained in the mixture in a second specific direction different from the first specific direction; and irradiating the second mixture with a second interference light, Forming a second multilayer structure in which a layer in which a photosensitive material is polymerized and a layer in which the light-effect material is not polymerized and becomes a liquid crystal layer are alternately laminated. A manufacturing method is obtained.

In the present invention, as the step of aligning the liquid crystal material in a specific direction, a rubbing step using an alignment film or a step of applying an electric field can be used.

In the present invention, S-polarized light can be used as one of the first interference light and the second interference light, and P-polarized light can be used as the other.

In the present invention, the angle of incidence of the first interference light and the angle of incidence of the second interference light are different from each other.

[0034]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a liquid crystal display device according to a first embodiment of the present invention. The liquid crystal display element of FIG. 1 corresponds to one pixel, and includes a light absorbing plate 11, a pair of transparent substrates 12, 13,
Alignment films 14 and 15 formed on the surfaces of transparent substrates 12 and 13, respectively, a first periodic structure 16 sandwiched between alignment films 14 and 15, and similarly sandwiched between alignment films 14 and 15 , And a second periodic structure 17 arranged in parallel with the first periodic structure 16.

The light absorbing plate 11 is incident on the liquid crystal display element, and the transparent substrate 13, the alignment film 15, the first periodic structure 16 or the second periodic structure 17, the alignment film 14, and the transparent substrate 12
Absorb light passing through. That is, the light absorbing plate 11 prevents light once entering the liquid crystal display element from being emitted to the outside again except for the light reflected by the first and second periodic structures 16 and 17. It is.

Normally, the light absorbing plate 11 is made of a material having an absorption wavelength characteristic and an absorption intensity characteristic necessary for absorbing all visible light. However, when a full color display is not intended, a material having an absorption wavelength characteristic and an absorption intensity characteristic that absorbs (or reflects) only light of a specific color may be selected. When this liquid crystal display element is used for a light control device that changes the transmission amount of incident light, an optical shutter, or the like, the light collecting plate is unnecessary.

The light absorbing plate 11 may be an inorganic material or an organic material as long as the material absorbs light. In addition, the light absorbing plate 11 can be made conductive and used as an electrode.

In the example of FIG. 1, the single light absorbing plate 11
However, a material in which a surface of a light absorbing substrate such as glass is coated with a light absorbing material (light absorbing film) may be used.
Alternatively, a light absorption film may be directly formed on the transparent substrate 12 as the light absorption plate 11.

When a light absorbing film is formed on the surface of the light absorbing substrate, either the light absorbing substrate or the light absorbing film may face the transparent substrate 12. The light absorbing substrate is a transparent substrate 12
, The light-absorbing substrate must be transparent. Conversely, when the light absorbing film faces the transparent substrate 12, the light absorbing substrate does not need to be transparent.

The transparent substrates 12, 13 are for holding the first periodic structure 16 and the second periodic structure 17, and are made of glass, plastic, or metal.

The alignment films 14 and 15 are made of the first periodic structure 1
This is for aligning the liquid crystal material contained in the sixth and second periodic structures 17. As the alignment films 14 and 15, for example, a polymer film such as a polyimide film or an inorganic material film can be used. Here, as the polyimide film, a soluble type in which polyimide or the like is dissolved in a solvent, or a sintering type in which sintering is performed to form polyimide can be used.

As shown in FIG. 2, the alignment film 14 has a first
A first region 21 corresponding to the second periodic structure and a second region 22 corresponding to the second periodic structure are formed.
The first region and the second region are rubbed in directions different from each other (here, directions orthogonal to each other). In the example of FIG. 2, in the first region, the rubbing process is performed in the right direction of the figure as shown by an arrow 23, and in the second region, as shown by an arrow 24, It is performed in the upward direction in the figure. The alignment film 15 is also subjected to a rubbing treatment similarly to the alignment film 14. However, the rubbing direction of the alignment film 15 is shown in FIG.
In this state, the alignment is performed in the same direction as the rubbing direction of the alignment film 14. As a result, the alignment films 14 and 15
The liquid crystal material in the first periodic structure and the liquid crystal material in the second periodic structure are parallel-aligned in directions different from each other.

Each of the first periodic structure 16 and the second periodic structure 17 has a multilayer structure in which liquid crystal layers and polymer layers are alternately laminated. Since the refractive index of the liquid crystal layer changes according to the strength of the applied electric field, these multilayer structures reflect or transmit light of a specific wavelength according to the applied voltage, based on the principle of an interference filter. Transmit all light of wavelengths other than.

In order to make the wavelength of light reflected / transmitted by the first periodic structure 16 and the wavelength of light reflected / transmitted by the second periodic structure 17 different from each other, the first
The periodic structure 16 and the second periodic structure have different layer thicknesses (repetition periods) of the liquid crystal layer and the polymer layer.

Each liquid crystal layer of the first periodic structure 16 and the second periodic structure 17 is made of a smectic liquid crystal (preferably a ferroelectric liquid crystal, an antiferromagnetic liquid crystal, or a ferrielectric liquid crystal) as a liquid crystal material. ). Further, each polymer layer of the first periodic structure 16 and the second periodic structure 17 is a liquid crystal monomer (preferably, a photocurable material).
Liquid crystal monomer).

Next, a method for manufacturing the liquid crystal display device will be described.

First, a pair of transparent substrates 12 and 13 are prepared. Then, alignment films 14 and 15 are formed on the surfaces of the substrates 12 and 13, respectively, and rubbing is performed on the surfaces.

To form two regions rubbed in different directions on the respective surfaces of the alignment films 14 and 15, for example, the following is performed.

First, the surface of the alignment film is rubbed along the first alignment direction. Then, a specific region (a region to be left rubbed in the first alignment direction) on the obtained surface is covered with a resist material. Next, the surface of the alignment film is moved to the first position.
Is rubbed along a second alignment direction different from the alignment direction of Finally, by peeling the resist material from the alignment film, two regions rubbed in different directions can be obtained. By using this method (by repeating the above operation), it is possible to form three or more regions rubbed in different directions.

After the surfaces of the alignment films 14 and 15 are rubbed, the transparent substrates 12 and 13 are positioned at predetermined intervals so that the rubbed surfaces face each other. In order to maintain the predetermined interval, a spacer or the like may be used. Then, along the periphery of the transparent substrates 12 and 13, the space between them is sealed except for a part.

Next, a mixture of a liquid crystal material and a photocurable material is prepared. Then, this mixture is applied to the transparent substrate 12.
And 13, more precisely, between the alignment films 14 and 15. Then, the space between the transparent substrates 12 and 13 is completely sealed. Thus, when the mixture is sandwiched between the pair of transparent substrates 12 and 13, the liquid crystal material contained in the mixture,
The liquid crystal monomer is affected by the alignment films 14 and 15 and is oriented along a direction parallel to the rubbing direction.

Subsequently, the mixture sandwiched between the transparent substrates 12 and 13 is irradiated with interference light to partially cure the photocurable material. At this time, the laser interference light may be separately radiated to the portion to be the first periodic structure 16 and the portion to be the second periodic structure 17, or may be radiated simultaneously. Is also good. The interference light can be obtained, for example, by irradiating two laser beams having the same wavelength from both the transparent substrate 12 side and the transparent substrate 11 side.

The portion to be the first periodic structure 16 and the second
When separately irradiating the part to be the periodic structure 17 with the interference light, first mask the part to be the second periodic structure 17 so as not to be irradiated with the interference light. Then, the mixture is irradiated with laser interference light. Then, the photocurable material is hardened at a portion where the laser interference light reinforces (a bright portion of the interference fringes). That is, the liquid crystalline monomer is polymerized. On the other hand, the part where laser interference light weakens (the dark part of interference fringes)
Does not cure the photocurable material. As a result, a first periodic structure 16 having a structure in which liquid crystal layers and polymer layers are alternately stacked is obtained.

Next, the mask for preventing the part to be the second periodic structure 17 from being irradiated with the interference light is removed, and the first periodic structure 16 is masked so as not to be irradiated with the interference light. Then, by changing the wavelength of the laser light or changing the incident angle of the laser light, the distance between the mutually intensifying portions of the interference light (interval of the interference fringes) is changed. Irradiation is performed on a portion to be the second periodic structure 17. In this manner, the liquid crystal layer and the polymer layer are alternately laminated, and the layer pressure thereof is different from that of the first periodic structure 16 in the second period.
Is obtained. Note that it is desirable to use polarized laser light having a vibration direction parallel to the orientation direction of the mixture as the laser interference light to be used. That is, if the laser interference light (two laser beams) used when forming the first periodic structure 16 is S-polarized, the second periodic structure 1
It is desirable that the laser interference light (two laser light beams) used when forming 7 is P-polarized light.

When simultaneously irradiating the portion to be the first periodic structure 16 and the portion to be the second periodic structure 17 with interference light, two types of laser interference having different intervals of interference fringes are used. The mixture is irradiated simultaneously with light. At this time, as one laser interference light, a polarization interference light whose oscillation direction is parallel to the orientation direction of the portion to be the first periodic structure 16 is used, and as the other laser interference light, the oscillation direction is the second interference interference light. By using the polarization interference light parallel to the orientation direction of the portion to be the periodic structure 17, the two periodic structures 16, 17 can be used.
Can be produced simultaneously. For example, if one polarization interference light is S-polarization, the other may be P-polarization.

After that, the light absorbing plate 11 is placed on the transparent substrate 12.
The liquid crystal display element of FIG. 1 is attached by bonding or the like.
Complete.

Here, regarding the formation of the electrodes,
Although the description is omitted, the liquid crystal display element according to the present embodiment can be driven by any of the simple matrix driving method and the active matrix driving method, and depending on the driving method, the liquid crystal display element such as an electrode and an active element is driven. The formation is performed (or a transparent substrate on which these are formed is used). The electrode is, for example, a wall-type electrode 31 as shown in FIG.
(The liquid crystal display element of FIG. 3 corresponds to a third embodiment described later.
Covered with. ). As the active element, a thin film transistor (TFT) element, a metal-insulator-metal (MIM) element, or the like can be used.

Next, the operation of the liquid crystal display device will be described with reference to FIGS. Note that here, the first
It is assumed that the periodic structure 16 is configured as a blue element that reflects / transmits blue light, and the second periodic structure 17 is configured as a green element that reflects / transmits green light.

When no voltage is applied to the liquid crystal display element, as shown in FIG. 4 or FIG. 5, the smectic liquid crystal molecules 41 of the blue element are aligned along the left and right directions in the figure, and the green element of the green element is oriented. The smectic liquid crystal molecules 42 are aligned along the vertical direction in the figure. In this case, the layer surface 43 of the smectic liquid crystal layer of the blue element and the layer surface 44 of the smectic liquid crystal layer of the green element are as shown by broken lines in FIG. 4 or FIG. The spontaneous polarization directions of the smectic liquid crystal molecules 41 and 42 are as indicated by arrows 45 and 46, respectively. Since both the blue and green elements have a refractive index difference between the liquid crystal layer and the polymer layer, they reflect light (blue and green, respectively) having a wavelength according to the layer thickness (periodic interval). I do. As a result, this liquid crystal display element displays a color in which blue and green are mixed in a state where no electric field is applied.

An electric field parallel to the alignment direction of the blue element and perpendicular to the alignment direction of the green element with respect to the liquid crystal display element (FIG. 4 and FIG. 47 is indicated by a dashed line), only the liquid crystal molecules 42 whose spontaneous polarization direction matches the electric field direction respond to the applied electric field, and the liquid crystal molecules 41 whose spontaneous polarization direction is orthogonal to the electric field direction do not respond. . That is, the liquid crystal molecules 42 of the green element
Only respond to the applied electric field. As a result, the difference in the refractive index between the liquid crystal layer and the polymer layer in the green element is reduced, and the reflectance (transmittance) for green light changes. That is, the amount of green light reflected by the green element decreases, and the color displayed by this liquid crystal display element becomes blue.

On the other hand, when an electric field perpendicular to the alignment direction of the blue element and parallel to the alignment direction of the green element is applied to this liquid crystal display element, the liquid crystal molecules 4 of the blue element
Only one responds to the applied electric field. As a result, the difference in the refractive index between the liquid crystal layer and the polymer layer in the blue element becomes smaller, and the reflectance (transmittance) for blue light changes. That is, the amount of blue light reflected by the blue element decreases, and the color displayed by the liquid crystal display element becomes green.

When an arc-shaped electric field (the lines of electric force 61 are indicated by dashed lines) is applied to this liquid crystal display element as shown in FIG. In response to electric field vector components 62 and 63 perpendicular to the alignment direction, the refractive index of the liquid crystal layer changes in both. As a result, the transmittance of the blue and green elements changes, and the color displayed on the liquid crystal display element changes. The change in the transmittance between the blue element and the green element can be controlled by the intensity of the applied electric field and the shape (for example, curvature) of the lines of electric force. That is, in this liquid crystal display element, the blue element and the green element can be controlled at once using a common electric field. Therefore, in practice, display of colors from blue to green can be realized with one pixel by control using a common electric field.

In the above embodiment, the case where the domain formed by each periodic structure is rectangular has been described. However, the present invention is not limited to this. The domain may be triangular as shown in FIG. As shown in FIG. 8, domains intermingled with each other in a complex shape (for example, a white portion in the figure corresponds to the first periodic structure, and a hatched portion in the figure corresponds to the second periodic structure). Yes) is also possible.

Next, a second embodiment of the present invention will be described with reference to FIG.

The liquid crystal display device of FIG. 9 differs from the first embodiment in that a first periodic structure 91 and a second periodic structure 92 are stacked on each other. Also, alignment films 93 and 94 formed on the surfaces of the transparent substrates 12 and 13
Is different from the first embodiment in that each rubbing direction is one direction. For example, the alignment film 93
Is rubbed in the right direction in the figure as shown by an arrow 95, and the alignment film 94 is rubbed in a direction perpendicular to the rubbing direction of the alignment film 93, that is, as shown by an arrow 96 in the right back direction. Is done.

The first periodic structure 91 and the second periodic structure 92 can be simultaneously manufactured by the same method as in the first embodiment. That is, by simultaneously irradiating two laser interference lights in which the intervals between the interference fringes are different, the polarization directions are orthogonal to each other, and the polarization directions are parallel to the rubbing directions of the alignment films 93 and 94, respectively, the wavelengths different from each other are obtained. The first periodic structure and the second periodic structure that reflect / transmit light can be manufactured at the same time.

Next, a third embodiment of the present invention will be described with reference to FIG.

The liquid crystal display device shown in FIG. 10 has a first periodic structure 101, a second periodic structure 102, and a third periodic structure 103. Also, this liquid crystal display element
An alignment film 104 sandwiched between the transparent substrate 12 and the first periodic structure 101; an alignment film 105 sandwiched between the first periodic structure 101 and the second periodic structure 102; 2
And an alignment film 106 interposed between the periodic structure 102 and the third periodic structure 103. Further, this liquid crystal display element includes a third periodic structure 103 and a transparent substrate 13.
And a protective film 107 sandwiched between the two.

The rubbing directions of the alignment films 104, 105 and 106 are different by 60 degrees. Then, the liquid crystal molecules included in the liquid crystal layer of the first periodic structure 101 are aligned parallel to the rubbing direction of the alignment film 104. Also,
The liquid crystal molecules included in the liquid crystal layer of the second periodic structure 102 are aligned parallel to the rubbing direction of the alignment film 105. Further, the liquid crystal molecules included in the liquid crystal layer of the third periodic structure 103 are aligned parallel to the rubbing direction of the alignment film 106. As described above, in the present embodiment, the liquid crystal molecules of the three periodic structures have different alignment directions by 60 degrees.

Next, a method for manufacturing the liquid crystal display device of the present embodiment will be described.

First, an alignment film material is applied on the transparent substrate 12 to form an alignment film 104. Then, the surface is rubbed in the first direction.

Next, a mixture of a liquid crystal material and a photocurable material is applied on the alignment film 104. Then, the mixture is irradiated with first interference light having a first interference fringe interval to form a multilayer structure in which liquid crystal layers and polymer layers are alternately stacked, that is, a first periodic structure 101. . Note that it is desirable to use polarized light having a vibration direction parallel to the alignment direction of the liquid crystal molecules as the interference light applied to the mixture.

Next, an alignment film material is applied on the first periodic structure 101 to form an alignment film 105. And the first
The surface is rubbed in the second rubbing direction inclined at an angle of 60 degrees with respect to the direction.

Next, a mixture of a liquid crystal material and a photocurable material is applied on the alignment film 105. A second interference light having a second interference fringe interval different from the first interference fringe interval is irradiated thereon, and the second periodic structure 102 is manufactured. Here, it is preferable that the interference light irradiating the mixture be polarized light having a vibration direction parallel to the alignment direction of the liquid crystal molecules.

Subsequently, an alignment film material is applied on the second periodic structure 102 to form an alignment film 106. And
The surface is rubbed in a third direction inclined 60 degrees with respect to the second rubbing direction (inclined 120 degrees with respect to the first rubbing direction).

Then, a mixture of a liquid crystal material and a photocurable material is applied on the alignment film 106. And a third laser beam having an interference fringe interval different from that of the first and second laser interference beams.
The mixture is irradiated with the above laser interference light to form the third periodic structure 103. Note that, similarly to the above, it is desirable to use polarized light having a vibration direction parallel to the orientation direction of the liquid crystal molecules as the interference light applied to the mixture.

Thereafter, the transparent substrate 13 is attached to the surface of the third periodic structure 103. Note that a protective film 107 is formed on the surface of the transparent substrate 13. This protective film 1
Reference numeral 07 denotes an adhesive, a polymer film, an alignment film, or the like. When the protective film 107 is an alignment film, the rubbing direction must match the alignment direction of the alignment film 106. Note that this protective film is not always necessary.

In this embodiment, the method of aligning the liquid crystal molecules using the alignment film has been described. However, when each periodic structure is formed, an electric field may be applied to align the liquid crystal molecules. .

The liquid crystal display device thus manufactured can simultaneously control three colors by applying an electric field having an electric field vector component in three directions.

In this embodiment, the case where three periodic structures are stacked has been described. However, it is of course possible to arrange each periodic structure in a plane so as to form a domain. It is also possible to produce four or more periodic structures. When four periodic structures are manufactured, for example, the orientation direction is (180 degrees / 4 =) 4
What is necessary is just to make it differ every 5 degrees. In the case of manufacturing five periodic structures, it is sufficient to make them different by (180 degrees / 5 =) 36 degrees.

As described above, the present invention has been specifically described based on some embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. is there.

[0083]

According to the liquid crystal display device of the present invention, a plurality of periodic structures having different alignment directions are formed in one pixel, so that the HPDLC devices of each color can be driven at once. A color HPDLC element having high light use efficiency with a simple element structure can be provided.

Further, according to the present invention, the structure of the HPDLC element capable of color display is simplified, so that the manufacturing process can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a rubbing direction of an alignment film used in the liquid crystal display device of FIG.

FIG. 3 is a diagram for explaining an electrode configuration for driving the liquid crystal display device of FIG. 1;

FIG. 4 is a diagram for explaining a method of driving the liquid crystal display element of FIG.

FIG. 5 is a diagram for explaining a method of driving the liquid crystal display device of FIG. 1;

FIG. 6 is a diagram for explaining a method of driving the liquid crystal display device of FIG. 1;

FIG. 7 is a view for explaining another example of the rubbing direction of the alignment film used in the liquid crystal display device of FIG.

8 is a diagram for explaining still another example of the rubbing direction of the alignment film used in the liquid crystal display device of FIG.

FIG. 9 is a schematic diagram illustrating a configuration of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 10 is a schematic sectional view showing a configuration of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 11 is a schematic sectional view showing a configuration of a conventional liquid crystal display element.

FIG. 12 is a schematic sectional view showing another configuration example of a conventional liquid crystal display element.

FIG. 13 is a cross-sectional view for explaining a problem of a conventional liquid crystal display element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Light absorption plate 12, 13 Transparent substrate 14, 15 Alignment film 16 1st periodic structure 17 2nd periodic structure 21 1st area 22 2nd area 31 Wall type electrode 32 Insulating film 41 Blue element smectic Liquid crystal molecules 42 Smectic liquid crystal molecules of green device 43 Layer surface of smectic liquid crystal layer of blue device 44 Layer surface of smectic liquid crystal layer of green device 47 Line of electric force 61 Line of electric force 62, 63 Electric field vector component 91 First periodic structure 92 First 2 periodic structure 93,94 alignment film 101 first periodic structure 102 second periodic structure 103 third periodic structure 104,105,106 alignment film 107 protective film 111 light absorption plate 112,113 transparent substrate 114, 115 Transparent electrode 116 Liquid crystal layer 117 Polymer layer 131 Active element 132 Contact hole 133 Insulating layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/141 G02F 1/137 510 (72) Inventor Goro Saito 5-7-1 Shiba 5-chome, Minato-ku, Tokyo Within NEC Corporation (72) Inventor Kenichi Takatori 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation F-term (reference) 2H088 FA02 FA04 GA04 GA06 GA10 HA01 HA03 HA08 HA14 JA17 JA20 LA02 MA20 2H089 HA02 HA04 HA22 NA01 QA12 RA13 RA14 TA01 TA04 TA09 TA13 2H090 HB08Y JB02 JB03 KA11 KA12 KA14 KA15 LA02 LA03 LA04 MA15 MB01 2H093 NA07 NA16 NC34 NC38 NC41 ND17 ND53 ND54 ND60 NE01 NF17 NF20

Claims (22)

[Claims] A plurality of periodic structures in which liquid crystal layers and polymer layers are alternately laminated, wherein the plurality of periodic structures reflect or transmit light in specific frequency bands different from each other in accordance with an applied electric field. In the liquid crystal display device, the orientation directions of the liquid crystal materials of the liquid crystal layers of the plurality of periodic structures are set to directions different from each other, and a common electric field is applied to control the orientation directions at the same time. A liquid crystal display device wherein the periodic structures are simultaneously driven. 2. The liquid crystal display device according to claim 1, wherein the plurality of periodic structures form one pixel. 3. The liquid crystal display device according to claim 1, wherein said plurality of periodic structures are arranged so as to form respective domains. 4. The method according to claim 1, wherein the plurality of periodic structures are disposed between a pair of transparent substrates, and an alignment film is provided between the transparent substrate and the plurality of periodic structures. The liquid crystal display device according to claim 3. 5. The liquid crystal display device according to claim 1, wherein the plurality of periodic structures are stacked on each other. 6. The plurality of periodic structures are disposed between a pair of transparent substrates, between each of the transparent substrates and the periodic structure, and between the plurality of periodic structures. 6. The liquid crystal display device according to claim 5, further comprising an alignment film. 7. A plurality of periodic structures having two periodic structures, wherein the orientation direction of the liquid crystal material of one periodic structure is orthogonal to the orientation direction of the liquid crystal material of the other periodic structure. Claims 1, 2, 3, 4,
5 or 6, the liquid crystal display element. 8. A plurality of periodic structures having three periodic structures, wherein an orientation direction of the liquid crystal material of each periodic structure is 60 ° with an orientation direction of the liquid crystal material of another periodic structure. Claims 1, 2, and 3, characterized in that they are different.
3, 4, 5, or 6 liquid crystal display elements. 9. The liquid crystal material according to claim 1, wherein a smectic liquid crystal is used.
5, 6, 7, or 8 liquid crystal display elements. 10. The liquid crystal display device according to claim 9, wherein the smectic liquid crystal is a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or a ferrielectric liquid crystal. 11. A photo-curable material is used for the polymer layer.
6, 7, 8, 9, or 10 liquid crystal display elements. 12. The liquid crystal display device according to claim 11, wherein a liquid crystalline monomer is used as said photocurable material. 13. The liquid crystal display device according to claim 12, wherein a smectic liquid crystal monomer is used as said liquid crystal monomer. 14. Using a plurality of electric fields having electric field vectors having different directions or a single electric field having a plurality of electric field vector components having different directions, the reflectances for lights having different wavelengths can be simultaneously measured. Controlling, 1, 2, 3, 4, 5, 6, 7, 8,
9. A driving method of the liquid crystal display element of 9, 10, 11, 12, or 13. 15. A mixture obtained by mixing a liquid crystal material and a photocurable material is sandwiched between a pair of substrates, and the mixture sandwiched between these substrates is divided into a plurality of regions, and the liquid crystal is separated for each region. A step of orienting the materials in specific directions different from each other, irradiating the mixture with mutually different interference light for each of the plurality of regions, and a layer in which the photocurable material is polymerized and the light-effect material are polymerized. Forming a plurality of multilayer structures in which layers to be liquid crystal layers are alternately laminated.
A manufacturing method for manufacturing the liquid crystal display device of 10, 11, 12, or 13. 16. The method according to claim 15, wherein the step of aligning the liquid crystal material in a specific direction includes a rubbing step using an alignment film or a step of applying an electric field. 17. The method according to claim 15, wherein the plurality of regions are two regions, and the different interference lights are S-polarized light and P-polarized light. 18. The method for manufacturing a liquid crystal display device according to claim 15, wherein an incident angle of the interference light applied to the plurality of regions is changed for each region. 19. A step of positioning a first mixture obtained by mixing a liquid crystal material and a photocurable material on a substrate; and a step of aligning the liquid crystal material contained in the first mixture in a first specific direction. And irradiating the first mixture with the first interference light, and a layer in which the photocurable material is polymerized and a layer in which the light-effect material does not polymerize and become a liquid crystal layer are alternately laminated. A step of forming a first multilayer structure; a step of positioning a second mixture of the liquid crystal material and the photocurable material on the multilayer structure substrate; and the liquid crystal contained in the second mixture. A step of orienting the material in a second specific direction different from the first specific direction, and irradiating the second mixture with a second interference light, wherein a layer in which the photocurable material is polymerized; Layers that become liquid crystal layers without photopolymerizable material were alternately laminated Claim 1, characterized in that a step of forming a second multilayer structure,
A manufacturing method for manufacturing the liquid crystal display element of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13. 20. The method according to claim 19, wherein the step of aligning the liquid crystal material in a specific direction is a rubbing step using an alignment film or a step of applying an electric field. 21. The method according to claim 19, wherein one of the first interference light and the second interference light is S-polarized light and the other is P-polarized light. 22. The method according to claim 19, wherein an incident angle of the first interference light and an incident angle of the second interference light are different from each other.