JPH07110465A - High polymer dispersion type liquid crystal display element - Google Patents

Abstract

PURPOSE:To enable the execution of changeover of display from a dark state to a bright state and from the bright state to the dark state at a high speed and to enable time-division driving at a high duty by orienting liquid crystals in the state that the normal of the smectic layer structure thereof inclines at a prescribed angle of inclination with a direction perpendicular to the substrate plane. CONSTITUTION:A liquid crystal/high polymer composite film 10 is disposed between a pair of transparent substrates 1 and 2 formed with transparent electrodes 3, 4. This composite film 10 is formed to the structure obtd. by dispersing the ferroelectric liquid crystals 12 having the smectic layer structure into the high polymer layer 11. The ferroelectric liquid crystals 12 in the respective liquid crystal parts in the composite film 10 are oriented in the state that the normal O of the smectic layer structure inclines at the prescribed angle theta of inclination with the direction H perpendicular to the planes of the substrates 1, 2. The electric fields impressed on the composite film 10 by application of a voltage between the electrodes 3 and 4 of both substrates 1, 2, therefore, act diagonally with the normal O of the layer structure and the liquid crystal molecules 12a are arranged in the uniformly inclined state by such electric fields.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer dispersion type liquid crystal display device.

[0002]

2. Description of the Related Art Recently, polymer dispersion type liquid crystal display elements have been attracting attention as liquid crystal display elements. In this polymer dispersion type liquid crystal display element, a liquid crystal / polymer composite film in which a liquid crystal is dispersed in a polymer layer is provided between a pair of substrates on which electrodes are formed.

In the liquid crystal / polymer composite film of the polymer dispersion type liquid crystal display device, the liquid crystal is roughly confined in each void portion of the polymer layer polymerized to have a cross section like a sponge. There is a structure and a structure in which liquid crystal is microencapsulated and the liquid crystal capsules are dispersed in a polymer layer.A nematic liquid crystal with a positive dielectric anisotropy is used for both composite films. There is.

In this polymer dispersion type liquid crystal display device, an electric field is applied to the liquid crystal / polymer composite film to drive display, and the molecules of the liquid crystal in the composite film are randomly oriented in a non-electric field state. When an electric field is applied, the liquid crystal molecules are uniformly arranged in the direction of application of the electric field. Since the optical refractive index of the liquid crystal varies depending on the alignment state of the liquid crystal molecules, the liquid crystal in the composite film exhibits different refractive indexes depending on the non-electric field state and the electric field application state.

On the other hand, the composite film is composed of a liquid crystal substance and a polymer material in which the refractive index of the liquid crystal and the refractive index of the polymer layer in an electric field applied state are substantially equal to each other. In the state where the liquid crystal molecules are oriented in random directions, the refractive index of the polymer layer and the liquid crystal are different, and the light incident on the liquid crystal display element is scattered by the composite film, resulting in a dark state in which the display is clouded. Become.

Further, when a voltage is applied between the electrodes of both substrates, the liquid crystal molecules in the composite film are uniformly arranged in the direction of application of the electric field, that is, in the direction substantially perpendicular to the substrate surface, and the liquid crystal molecules are aligned. Since the refractive index of is almost equal to the refractive index of the polymer layer, incident light is transmitted through the composite film with little scattering, and a bright state is displayed by this non-scattered transmitted light.

That is, the polymer dispersion type liquid crystal display device displays a dark state and a bright state by utilizing the scattering and transmission of light in the liquid crystal / polymer composite film. Type liquid crystal display element can display light and dark without using a polarizing plate, and therefore, there is no light amount loss due to light absorption in the polarizing plate unlike the commonly used TN type liquid crystal display element. The feature is that the screen is much brighter than the display element.

[0008]

However, the conventional polymer-dispersed liquid crystal display element has a problem that it is difficult to perform time-divisional driving with high duty. This is a liquid crystal /
This is due to the responsiveness of the nematic liquid crystal used in the polymer composite film. Since the nematic liquid crystal has a slow response speed to the application of an electric field, it takes time for the liquid crystal molecules to rise from a random alignment state to a rise alignment.

Further, when the electric field applied state is changed to the non-electric field state, since the orientation of the liquid crystal molecules cannot be controlled by the electric field, the liquid crystal molecules are naturally returned to a random orientation, and therefore the liquid crystal molecules rise. The time from the aligned state to the random aligned state is considerably longer than the time required for the liquid crystal molecules to rise and align.

Therefore, the conventional polymer dispersion type liquid crystal display device cannot switch the display from the dark state to the bright state and from the bright state to the dark state at high speed, and therefore, the time division is performed with high duty. It is difficult to drive.

The present invention provides a polymer dispersion type liquid crystal display device capable of switching display from a dark state to a bright state and from a bright state to a dark state at high speed and capable of time-division driving at high duty. It is intended to be provided.

[0012]

A polymer-dispersed liquid crystal display device according to the present invention is a ferroelectric or antiferroelectric liquid crystal having a smectic layer structure in a polymer layer between a pair of substrates on which electrodes are formed. And a liquid crystal of each liquid crystal part in the composite film has a predetermined tilt angle with respect to a direction in which the normal line of the smectic layer structure is perpendicular to the substrate surface. It is characterized in that it is oriented in a tilted state.

[0013]

In other words, the polymer dispersed liquid crystal display device of the present invention uses ferroelectric or antiferroelectric liquid crystal having a smectic layer structure as the liquid crystal of the liquid crystal / polymer composite film. Dielectric or antiferroelectric liquid crystal, in a non-electric field state, the liquid crystal molecules are arranged along a normal line of the smectic layer structure in a spiral shape in which a tilt direction with respect to the normal line is sequentially shifted layer by layer, When an electric field is applied in a direction intersecting the normal to the layer structure, the layers are arranged in a state in which the electric field is uniformly tilted in one direction depending on the polarity of the applied electric field.

The liquid crystal of each liquid crystal part in the composite film is
Since the normal of the layer structure is oriented with a predetermined inclination angle with respect to the direction perpendicular to the substrate surface, the electric field applied to the composite film by applying a voltage between the electrodes of both substrates is It acts diagonally to the normal of the layer structure, and the electric field causes the liquid crystal molecules to be uniformly tilted.

In this liquid crystal display element, the molecules of the ferroelectric liquid crystal of each liquid crystal portion in the composite film are arranged in a spiral along the normal line of the layer structure in the absence of an electric field to apply an electric field. Then, since the liquid crystal molecules are arranged in a state in which they are uniformly tilted in one direction with respect to the normal line, the change in the arrangement state of the liquid crystal molecules changes the optical refractive index of the liquid crystal in the entire liquid crystal portion. The electric field applied to the composite film is only an electric field having a polarity for orienting the liquid crystal molecules by inclining the liquid crystal molecules in a direction in which the angle with respect to the direction perpendicular to the substrate surface is large.

Therefore, the composite film is composed of a liquid crystal substance and a polymer material in which the refractive index of the liquid crystal is substantially equal to the refractive index of the polymer layer in either the non-electric field state or the electric field applied state. Then, by controlling the application of the electric field to the composite film, it is possible to display the dark state and the bright state by utilizing the scattering and transmission of light in the composite film.

Further, since the ferroelectric or antiferroelectric liquid crystal has a good responsiveness to an electric field, when an electric field higher than a threshold voltage is applied, liquid crystal molecules are promptly made uniform from a helical arrangement state. In addition, the liquid crystal molecules are arranged in a twisted state with a helical pitch peculiar to the liquid crystal in the non-electric field state, so that even when the electric field is applied to the non-electric field state, the liquid crystal molecules are It quickly returns to the original spiral arrangement state.

Therefore, according to the polymer dispersion type liquid crystal display element of the present invention, it is possible to switch the display from the dark state to the bright state and from the bright state to the dark state at a high speed. Divided drive is possible.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing the principle configuration of a polymer dispersed liquid crystal display device according to a first embodiment of the present invention.
The liquid crystal display element of this example uses a ferroelectric liquid crystal as the liquid crystal of the liquid crystal / polymer composite film.

This polymer dispersion type liquid crystal display device comprises a liquid crystal / polymer composite film 10 provided between a pair of transparent substrates 1 and 2 on which transparent electrodes 3 and 4 are formed.
Has a structure in which a ferroelectric liquid crystal 12 having a smectic layer structure is dispersed in a polymer layer 11.

The liquid crystal / polymer composite film 10 is formed by a method called a photopolymerization phase separation method. This photopolymerization phase separation method is performed between a pair of substrates 1 and 2 facing each other.
This is a method of filling a mixed solution of a polymer material that undergoes a polymerization reaction by light and liquid crystal 12, and irradiating the mixed solution with ultraviolet rays to photopolymerize the polymer material. Alternatively, the polymer material in the state of an oligomer is converted into a radical by the double bond being broken, and the radicals of adjacent molecules are combined with each other to form a polymer,
The liquid crystal 12 is phase-separated by polymerizing the polymer material, and the composite film 10 in which the liquid crystal 12 is dispersed in the polymer layer 11 is formed.
Is formed.

The liquid crystal / polymer composite film 10 formed by this photopolymerization phase separation method is a polymerized polymer layer 11
Has a sponge-like cross section, and this polymer layer 1
Since the liquid crystal 12 is confined in each of the gaps of No. 1, each liquid crystal part (portion in which the liquid crystal 12 is confined) A in the composite film 10 has a complicated shape. A is shown in a simple shape.

Further, in the ferroelectric liquid crystal 12 of each liquid crystal portion A in the composite film 10, the normal line of the smectic layer structure (hereinafter referred to as the layer structure normal line) O is in the direction perpendicular to the substrates 1 and 2 ( Hereinafter, it is oriented in a state of being inclined at a predetermined inclination angle θ with respect to H).

The layer structure normal O to the substrate normal H
Of the liquid crystal molecule 12a is sufficiently smaller than the tilt angle of the liquid crystal molecules 12a with respect to the layer structure normal O, and therefore the layer structure normal O is only slightly tilted with respect to the substrate normal H.

In order to orient the ferroelectric liquid crystal 12 as described above, after the liquid crystal / polymer composite film 10 is formed, it is heated to a temperature at which the ferroelectric liquid crystal 12 exhibits an isotropic phase, and the state is maintained. By applying an electric field in a direction tilted at a predetermined angle with respect to the direction perpendicular to the surfaces of the substrates 1 and 2, re-orientation processing for lowering the liquid crystal 12 to a temperature exhibiting a ferroelectric phase can be performed while maintaining this electric field application state. This re-orientation treatment allows the ferroelectric liquid crystals 12 in all the liquid crystal parts A of the composite film 10 to have the layer structure normal O aligned in the direction inclined by the tilt angle θ with respect to the substrate normal H. Oriented with a smectic layer structure.

That is, the above-mentioned polymer dispersed liquid crystal display device uses a ferroelectric liquid crystal 12 having a smectic layer structure as the liquid crystal of the liquid crystal / polymer composite film 10, and the ferroelectric liquid crystal 12 is , In the state of no electric field, liquid crystal molecules 12
As shown in FIG. 1, a is arranged in a spiral shape in which the inclination direction with respect to the normal O to the normal to the layer structure normal O is sequentially shifted layer by layer and intersects the normal to the layer structure normal O. When an electric field in a direction is applied, the cells are arranged in a state in which they are uniformly tilted in one direction with respect to the normal O depending on the polarity of the applied electric field.

The liquid crystal 12 of each liquid crystal portion A in the composite film 10 is oriented in a state where the layer structure normal O is inclined with respect to the substrate normal H by the above-mentioned inclination angle θ, and The composite film 10 is formed by applying a voltage between the electrodes 3 and 4 of the substrates 1 and 2.
Is applied obliquely to the layer structure normal O, and the electric field causes the liquid crystal molecules 12a to be uniformly tilted.

Further, the inner width of the gap portion of the polymer layer 11 of the liquid crystal / polymer composite film 10 is sufficiently larger than the spiral pitch of the ferroelectric liquid crystal 12, so that it is confined in the gap portion of the polymer layer 11. The molecules 12a of the liquid crystal 12 thus obtained change the alignment state without being restricted by the polymer layer 11.

In this liquid crystal display device, the molecules 12a of the ferroelectric liquid crystal 12 of each liquid crystal part A in the composite film 10 are used.
However, in the state of no electric field, they are arranged in a spiral along the layer structure normal line O, and when an electric field is applied, they are arranged in a state of being uniformly tilted in one direction with respect to the normal line O, so that the liquid crystal molecules 12a are arranged. Due to the change in the state, the light refractive index of the liquid crystal 12 in the entire liquid crystal part A changes.

In the display drive of this liquid crystal display device, the electric field applied to the composite film 10 is only the electric field of the polarity for orienting the liquid crystal molecules 12a by inclining them in the direction in which the angle with respect to the normal H to the substrate surface increases. In FIG. 1, L is a liquid crystal molecule 12 when an electric field of the above polarity is applied to the composite film 10.
The arrangement direction of a is shown.

If an electric field of opposite polarity is applied to the composite film 10, the liquid crystal molecules 12a are opposite to the layer structure normal line O, which is opposite to the liquid crystal molecule alignment direction L when the electric field is applied as shown in FIG. However, when the orientation of the liquid crystal molecules 12a changes until it becomes parallel to the substrate normal line H, the liquid crystal molecules 1
The direction of the spontaneous polarization of 2a is orthogonal to the direction of the applied electric field, and the rotation vector due to the electric field does not act on the liquid crystal molecules 12a, so that the alignment state of the liquid crystal molecules 12a does not change beyond that.

In the above liquid crystal display device, the liquid crystal / liquid crystal display device is driven by the non-electric field state and the application of the electric field of the above-mentioned polarity.
Since the optical refractive index of the liquid crystal 12 of the polymer composite film 10 is changed, the refractive index of the liquid crystal 12 and the refractive index of the polymer layer 11 in the composite film 10 in either a non-electric field state or an electric field application state are almost the same. If the liquid crystal substance and the polymer material are made equal to each other, it is possible to control the application of an electric field to the composite film 10 to utilize the scattering and transmission of light in the composite film 10 to produce a dark image. A state and a bright state can be displayed.

That is, the refractive index of the liquid crystal 12 in the entire liquid crystal part A in the non-electric field state is n ₁ , the refractive index of the liquid crystal 12 in the whole liquid crystal part A in the electric field applied state is n _2, and the refraction of the polymer layer 11 is made. Assuming that the rate is n ₀ , for example, if n ₁ = n ₀ , light is transmitted through the composite film 10 with little scattering and the display is in a bright state in the non-electric field state. When an electric field of one polarity or the opposite polarity is applied to the composite film 10 by applying a voltage between the first and second electrodes, light is scattered due to the difference in the refractive index between the liquid crystal 12 and the polymer layer 11, and the display is in a dark state. .

If n ₂ = n ₀ , in the absence of an electric field, light is scattered due to the difference in refractive index between the liquid crystal 12 and the polymer layer 11, and the display is in a dark state. When an electric field of one polarity or the opposite polarity is applied to, the light is transmitted through the composite film 10 with almost no scattering, and the display is in the bright state.

Further, since the ferroelectric liquid crystal 12 has a good responsiveness to an electric field, when an electric field higher than the threshold voltage is applied, the liquid crystal molecules 12a are quickly changed from a spiral arrangement state to a uniform arrangement state. In addition, since the liquid crystal molecules 12a are arranged in a twisted state at a helical pitch peculiar to the liquid crystal in a non-electric field state, even when the electric field is applied to the non-electric field state, the liquid crystal molecules 12a are in a uniform arrangement state. It quickly returns to the original spiral arrangement state.

Therefore, according to the polymer dispersion type liquid crystal display device, it is possible to switch the display from the dark state to the bright state and from the bright state to the dark state at a high speed, so that the time division driving with a high duty is performed. Is possible.

FIG. 2 is a sectional view of a part of a liquid crystal element showing a specific example in which the first embodiment is applied to an active matrix liquid crystal element. The active matrix liquid crystal element is a reflection type in which a reflection plate 32 is arranged on the back surface thereof.

In FIG. 2, the lower substrate 21 is the back side substrate of the liquid crystal element, and the upper substrate 22 is the front side substrate. These substrates 21 and 22 are transparent substrates made of a glass plate or the like, and the back side substrate 21 has a plurality of transparent pixel electrodes 23 arranged in the row direction and the column direction, and each of the pixel electrodes 2
3, a plurality of active elements 24 respectively corresponding to 3 are provided, and the front surface side substrate 22 is provided with a transparent counter electrode 30 which is opposed to all the pixel electrodes 23 of the back surface side substrate 21 over substantially the entire surface thereof. ing.

The active element 24 is, for example, a TFT (thin film transistor).
The gate electrode 25 formed on one surface and the gate electrode 2
5 and a-S formed on the gate insulating film 26 so as to face the gate electrode 25.
Semiconductor film 27 made of i (amorphous silicon) or the like
And a source electrode 28 and a drain electrode 29 formed on both sides of the semiconductor film 27.

Although not shown, a gate line (address line) for supplying a gate signal to the TFT 24 and a data line for supplying a data signal according to image data to the TFT 24 are wired on the rear substrate 21. The gate electrode 25 of the TFT 24 is formed integrally with the gate line, and the drain electrode 29 is connected to the data line.

Further, the back surface side substrate 21 is provided with a phosphor film 31 corresponding to each pixel electrode 23 arranged on the back surface side substrate 21, which emits fluorescence when exposed to light. The phosphor film 31 is a transparent resin base material in which fine granular fluorescent substances are mixed in a scattered state.

In this embodiment, the phosphor film 31 is used.
As a plurality of phosphor films that emit fluorescence of different colors, for example, a phosphor film that emits red fluorescence, a phosphor film that emits green fluorescence, and a phosphor film that emits blue fluorescence are used. Body films are provided alternately corresponding to the pixel electrodes 23.

The phosphor film 31 is formed on the back surface of the substrate 21 and is covered with the gate insulating film 26 of the TFT 24. The gate insulating film 26 is a transparent film made of Si (silicon nitride) or the like, and the pixel electrode 23 is provided on the gate insulating film 26 and has one end connected to the source electrode 28 of the corresponding TFT 24. Has been done.

The back-side substrate 21 and the front-side substrate 22 are joined to each other at their outer peripheral edges via a frame-shaped sealing material (not shown), and are surrounded by the sealing material between the substrates 21 and 22. The liquid crystal / polymer composite film 10 described above is provided in the separated region.

This liquid crystal display device is composed of a pair of substrates 2.
After bonding 1, 22 at their outer peripheral edges via a sealing material (not shown), an injection port formed by removing a part of the sealing material between the two substrates 21, 22
A liquid crystal / polymer composite film 10 is formed by injecting and filling a mixed solution of a polymer material that undergoes a polymerization reaction by light and a ferroelectric liquid crystal by a vacuum injection method, and then the back side substrate 21. The reflection plate 32 is adhered to the outer surface (back surface) of the above to complete.

The reflection plate 32 is formed by applying a reflection film 34 to the surface of a base sheet 33 made of a resin film. The reflection film 34 is, for example, Al (aluminum) whose surface is roughened. It is a reflective film.

That is, the active matrix liquid crystal display device is for displaying by utilizing the scattering and transmission of light in the liquid crystal / polymer composite film 10 described above, and the composite film 10 has a ferroelectric property in the liquid crystal. Since the liquid crystal 12 is used, it is possible to switch the display from the dark state to the bright state and from the bright state to the dark state at high speed, and therefore, high-duty time-division driving is possible.

Further, in this active matrix liquid crystal display element, since the back surface side substrate 11 is provided with the phosphor film 31 which emits fluorescence upon receiving light, corresponding to each pixel electrode 23, this phosphor is used. Since the emitted light becomes brighter due to the fluorescence emitted from the film 31, it is possible to display a color image with a bright screen and high contrast.

That is, in this liquid crystal display device, a bright display is displayed by the light that has passed through the liquid crystal / polymer composite film 10 and is reflected by the reflection plate 32 on the back surface of the device. A certain amount of the emitted light is absorbed by the fluorescent substance in the phosphor film 31 provided on the back side substrate 11 to generate fluorescence when passing through the phosphor film 31, so that the reflection plate 32 is used.
The light reflected by and the fluorescence emitted by the phosphor film 31 are transmitted through the composite film 10 again and emitted to the front surface side.

Therefore, the bright display of the liquid crystal display element is
The display is colored in the color of the fluorescence emitted by the phosphor film 31, and the fluorescent substance in the phosphor film 31 emits fluorescence not only in visible light but also in wavelengths outside the visible light band. Therefore, since the fluorescence emitted from the phosphor film 31 is light of high brightness, a color image with a bright screen and high contrast can be obtained.

In the active matrix liquid crystal display element shown in FIG. 2, the reflection plate 3 is provided on the outer surface of the rear substrate 21.
However, instead of the reflection plate 32, a reflection film may be provided on the inner surface side of the back-side substrate 21.

FIG. 3 is a sectional view of a part of a liquid crystal element showing another specific example in which the above-described first embodiment is applied to the active matrix liquid crystal element. This active matrix liquid crystal element has a pixel electrode 23 provided on the back substrate 21.
Is formed of an Al film or the like having a roughened surface, the pixel electrode 23 also serves as a reflection film, and the phosphor film 31 is provided on the pixel electrode 23. This is the same as the liquid crystal display element shown in 2.

The present invention is not limited to the reflective type,
It can also be applied to transmissive liquid crystal elements, and one of the substrates is provided with segment electrodes corresponding to the display pattern,
On the other hand, it can be applied to a segment display type liquid crystal element in which a common electrode is provided on the substrate.

Further, although the ferroelectric liquid crystal 12 is used as the liquid crystal of the liquid crystal / polymer composite film 10 in the first embodiment, the liquid crystal may be antiferroelectric liquid crystal. FIG. 4 is a diagram schematically showing the principle configuration of a polymer-dispersed liquid crystal display device according to a second embodiment of the present invention. The liquid crystal display device of this embodiment is composed of a liquid crystal / polymer composite film 10. The antiferroelectric liquid crystal 13 is used as the liquid crystal.

In this embodiment, the antiferroelectric liquid crystal 13 is used as the liquid crystal of the composite film 10, but the other structure is the same as that of the first embodiment shown in FIG. ,
Overlapping explanations are given the same symbols in the drawings and omitted.

Also in the liquid crystal display device of this embodiment, in the non-electric field state, the molecules 13a of the antiferroelectric liquid crystal 13 are inclined along the normal line O of the smectic layer structure sequentially with respect to each layer. It is arranged in a shifted spiral shape,
When an electric field in a direction intersecting the layer structure normal O is applied, the layers are arranged in a state of being uniformly inclined in one direction with respect to the normal O according to the polarity of the applied electric field.

Also in this embodiment, the antiferroelectric liquid crystal 13 of each liquid crystal portion A in the composite film 10 is in a state where the layer structure normal O is tilted at a predetermined tilt angle θ with respect to the substrate normal H. Therefore, the electric field applied to the composite film 10 by the application of the voltage between the electrodes 3 and 4 of the substrates 1 and 2 acts obliquely with respect to the layer structure normal O, and the liquid crystal is caused by the electric field. The molecules 13a are arranged in a state of being uniformly inclined.

Also in this liquid crystal display element, the molecules 13a of the antiferroelectric liquid crystal 13 of each liquid crystal part A in the composite film 10 are arranged spirally along the layer structure normal O in the non-electric field state. However, when an electric field is applied, the liquid crystal molecules are aligned in a state in which they are uniformly tilted in one direction with respect to the normal line O.
The liquid crystal 13 in the entire liquid crystal part A is changed by the change of the arrangement state of
The optical refractive index of changes. Also in this embodiment, the electric field applied to the composite film 10 is only the electric field of the polarity for orienting the liquid crystal molecules 13a by inclining them in the direction in which the angle with respect to the substrate normal H increases.

Therefore, the composite film 10 is formed of a liquid crystal substance and a polymer material such that the refractive index of the liquid crystal 13 and the refractive index of the polymer layer 11 are substantially equal in either the non-electric field state or the electric field application state. The composite membrane 1
By controlling the application of the electric field to 0, the composite film 1
It is possible to display the dark state and the bright state by utilizing the scattering and transmission of light at 0.

Also in the liquid crystal display element of this embodiment, since the antiferroelectric liquid crystal 13 has a good response to the electric field, when an electric field higher than the threshold voltage is applied, the liquid crystal molecules 13a are arranged in a spiral arrangement. From the state, the state is rapidly changed to a uniform state, and in the non-electric field state, the liquid crystal molecules 13a are arranged in a twisted state at a helical pitch peculiar to the liquid crystal,
Even when the electric field is turned off, the liquid crystal molecules 1
3a quickly returns from the uniform array state to the original spiral array state.

Therefore, also in the polymer dispersed liquid crystal display element of this embodiment, it is possible to switch the display from the dark state to the bright state and from the bright state to the dark state at a high speed, so that the time division is performed at a high duty. It can be driven.

The liquid crystal / polymer composite film 10 in the polymer dispersion type liquid crystal display device of the first and second embodiments described above is formed by the photopolymerization phase separation method. The composite film 10 may have a structure in which a liquid crystal is microencapsulated and the liquid crystal capsule is dispersed in a polymer layer.

[0063]

The polymer dispersed liquid crystal display device of the present invention is
A liquid crystal / polymer composite film in which a ferroelectric or antiferroelectric liquid crystal having a smectic layer structure is dispersed in a polymer layer is provided between a pair of substrates on which electrodes are formed, and in the composite film The liquid crystal of each liquid crystal part is characterized in that the normal line of the smectic layer structure is aligned at a predetermined tilt angle with respect to the direction perpendicular to the substrate surface, and thus the dark state From the light state to the light state and from the light state to the dark state can be switched at high speed, and therefore, high-duty time-division driving is possible.

[Brief description of drawings]

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

FIG. 2 is a partial cross-sectional view of a liquid crystal element showing a specific example in which the first embodiment of the present invention is applied to an active matrix liquid crystal element.

FIG. 3 is a partial cross-sectional view of a liquid crystal element showing another specific example in which the first embodiment of the present invention is applied to an active matrix liquid crystal element.

FIG. 4 is a diagram schematically showing the principle configuration of a polymer-dispersed liquid crystal display device according to a second embodiment of the present invention.

[Explanation of symbols]

 1, 2 ... Substrate 3, 4 ... Electrode 10 ... Liquid crystal / polymer composite film 11 ... Polymer layer A ... Liquid crystal part 12 ... Ferroelectric liquid crystal 12a ... Liquid molecule 13 ... Antiferroelectric liquid crystal 13a ... Liquid molecule

Claims (1)

[Claims] 1. A liquid crystal / polymer composite film in which a ferroelectric or antiferroelectric liquid crystal having a smectic layer structure is dispersed in a polymer layer between a pair of substrates on which electrodes are formed, and The liquid crystal of each liquid crystal portion in the composite film is oriented in a state where a normal line of the smectic layer structure is inclined at a predetermined inclination angle with respect to a direction perpendicular to the substrate surface. Dispersed liquid crystal display device.