JPH07140446A - Light scattering type liquid crystal element - Google Patents

Abstract

PURPOSE:To provide a wide visual field angle and high-grade display by forming the rear surface side substrate of a pair of front and rear transparent substrates as a flexible substrate consisting of a resin film and providing the outside surface of this rear side substrate with a reflecting member. CONSTITUTION:This high polymer dispersion type liquid crystal element is constituted by disposing a liquid crystal/high polymer combined film 16 formed by dispersing liquid crystals into a high polymer in a region enclosed by a sealing material 15 between a pair of the front and rear transparent substrates 11 and 12 and forming transparent electrodes 13, 14 respectively on the inside surfaces of both substrates 11 and 12. The front surface side substrate 11 consists of glass, etc., and the rear surface side substrate 12 is formed of the flexible substrate consisting of the transparent resin film, such as polyethylene terephthalate. The reflection member 17 consisting of a reflection film 17a consisting of an Al film, etc., and a phosphor film 17b is disposed on the rear surface thereof. As a result, the thickness of the rear surface side substrate 12 is made extremely small and, therefore, the distance from the surface of the liquid crystal/high polymer combined film 16 to the surface of the reflection member 17 is shortened and the missing width of the display when the display is viewed from a diagonal direction is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scattering type liquid crystal element.

[0002]

2. Description of the Related Art In a light-scattering type liquid crystal element, a liquid crystal layer is provided between a pair of front and back substrates provided with electrodes, in which the alignment state of liquid crystal molecules changes between a state in which transmitted light is scattered by an electric field and a state in which transmitted light is transmitted. As this light scattering type liquid crystal element, there is, for example, a polymer dispersion type liquid crystal layer in which a liquid crystal layer between a pair of substrates is a liquid crystal / polymer composite film.

FIG. 5 is a sectional view of a conventional polymer dispersion type liquid crystal element, and FIG. 6 is an enlarged view of a part thereof. In this polymer dispersion type liquid crystal element, a pair of front and back transparent substrates 1 and 2 made of a hard plate such as glass is bonded at a peripheral portion thereof with a frame-shaped sealing material 5, and the space between the substrates 1 and 2 is A liquid crystal / polymer composite film 6 is provided in a region surrounded by the sealing material 5,
Transparent electrodes 3 and 4 are formed on the inner surfaces of the substrates 1 and 2 (the surfaces facing the composite film 6), respectively.

This liquid crystal element is of a simple matrix type, for example, and one substrate, for example, the electrode 4 of the back substrate 2 has a plurality of scanning electrodes formed in parallel with each other, and the other substrate, that is, The electrodes 3 on the front side substrate 1 are a plurality of signal electrodes formed so as to be orthogonal to the scanning electrodes 4.

Further, the liquid crystal / polymer composite film 6 is one in which a liquid crystal is dispersed in a polymer.
As shown in FIG. 6, the liquid crystal 6 is provided in each gap of the polymer layer 6a which is polymerized so as to have a gap like a sponge.
b has a confined structure. The liquid crystal 6b
In general, a nematic liquid crystal having a positive dielectric anisotropy is used as.

The polymer dispersed liquid crystal device is driven by a display by applying an electric field between the electrodes 3 and 4 formed on the substrates 1 and 2, and is dispersed in the polymer of the composite film 6. The liquid crystal molecules of each liquid crystal portion (portion in which the liquid crystal is confined) are oriented in various directions in the non-electric field state in which no electric field is applied between the electrodes 3 and 4, and in this state, the composite film 6 The light passing through is scattered by the interface between the liquid crystal part and the polymer and the light scattering action of the liquid crystal part.

When an electric field higher than the threshold voltage of the liquid crystal 6b is applied between the electrodes 3 and 4, the liquid crystal molecules in each liquid crystal part of the composite film 6 are almost perpendicular to the substrates 1 and 2 due to the electric field. The light passing through the composite film 6 is transmitted with almost no light scattering effect.

That is, the polymer dispersion type liquid crystal device is
The display is performed by utilizing the scattering and transmission of light, and the pixel displayed at the intersection facing portion of the scanning electrode 4 of the rear surface side substrate 2 and the signal electrode 3 of the front surface side substrate 1 does not emit light when there is no electric field. Since it is displayed as white turbid light due to scattering of light and is displayed as high-intensity transmitted light when an electric field is applied, a polarizing plate with a low light transmittance is used.
It has the advantage that the screen is brighter than N-type liquid crystal elements.

Therefore, the polymer-dispersed liquid crystal element is generally used as a reflection type element by arranging the reflection film 7 on the outer surface of the backside substrate 2. A metal film such as an Al (aluminum) film is used for the reflection film 7, and the reflection film 7 is generally a base sheet 8 made of a resin film or the like.
Is deposited by vapor deposition or sputtering.

In this reflection type polymer dispersion type liquid crystal device, the light incident from the surface side thereof is reflected by the reflection film 7 through the liquid crystal / polymer composite film 6 and again passes through the composite film 6 to the surface. Since the light is emitted to the side, the light passing through the non-electric field portion is doubly scattered, and the contrast with the transmitted light passing through the electric field applying portion is increased.

In addition to the polymer dispersion type liquid crystal element described above, the light scattering type liquid crystal element also includes a phase transition (PC) effect type. This phase-transition-effect type liquid crystal element has a nematic phase of homeotropic molecular alignment and a helical molecular alignment with various helical axes oriented between a pair of substrates with electrodes formed and covered with an insulating film. A liquid crystal layer that undergoes a phase transition to an cholesteric phase by an electric field is provided. As the liquid crystal, a liquid crystal prepared by adding a cholesteric liquid crystal or a chiral nematic liquid crystal to a nematic liquid crystal is generally used.

In this phase-transition-effect type liquid crystal element, light passing through the liquid crystal layer is scattered because the helical axis of the liquid crystal is aligned in various directions in the absence of an electric field. When a constant electric field is applied, the liquid crystal molecules are homeotropically aligned, and the light passing through the liquid crystal layer is transmitted with almost no light scattering effect.

That is, the phase transition effect type liquid crystal element also displays by utilizing the scattering and transmission of light, and therefore has the advantage that the screen is bright. For this reason,
This phase transition effect type liquid crystal element is also generally a reflection type element in which a reflection film is arranged on the back surface thereof.

[0014]

However, the conventional light-scattering type liquid crystal element has good display quality when the display is viewed from the front direction, but the display quality is poor when viewed from an oblique direction, and therefore the display quality is However, there is a problem that the viewing angle range (hereinafter referred to as the viewing angle) in which a high-quality image can be viewed is narrow.

This will be described with respect to the conventional polymer dispersion type liquid crystal element shown in FIGS. 5 and 6. When the display of this liquid crystal element is viewed from the front direction (the normal direction of the liquid crystal element), the electric field The illuminated pixels displayed by the application appear to have a regular size.

However, when the display of this liquid crystal element is viewed in an oblique direction (direction inclined with respect to the normal line of the liquid crystal element) as indicated by an arrow in FIG. 6, a bright region (composite film 6) on the reflective film 7 is shown. The area A where the light transmitted through illuminates) and the visual field area B are displaced as shown in the figure.

In the polymer-dispersed liquid crystal device, the light incident on the region of the composite film 6 to which the electric field is applied passes through the composite film 6, but the light incident on the non-electric field region is on the composite film 6. Since the light is scattered in all directions, one side of the bright area A on the reflective film 7, that is, the side opposite to the direction of deviation of the visual area B, is the bright area A and the visual area B.
A shadow due to light scattering in the composite film 6 is formed over the width W corresponding to the amount of deviation from the above, and only the area C of the bright area A is visible. Therefore, the illuminated pixel seen from the front surface side of the liquid crystal element has a shape in which one side thereof is chipped off over the width W.

On the outer side of the other side of the bright area A on the reflection film 7, the bright area A is provided together with the lighting pixel.
Although a part of the region adjacent to is visible over the width W corresponding to the amount of deviation between the bright region A and the visual field region B described above, since this portion is also a shadow due to light scattering in the composite film 6,
Only the area C of the bright area A is visible as a lit pixel.

The width W of the lit pixel is determined by the viewing angle (angle with respect to the normal to the liquid crystal element) and the distance from the surface of the composite film 6 (the surface in contact with the front substrate 1) to the reflective film 7 surface. When the display of the liquid crystal element is viewed at a constant viewing angle, the longer the distance from the surface of the composite film 6 to the reflective film 7 surface, the larger the chipping width W of the lit pixel.

Although the distance from the surface of the composite film 6 to the surface of the reflective film 7 corresponds to the sum of the film thickness of the composite film 6 and the plate thickness of the back side substrate 2, In order to obtain a sufficient scattering effect, the thickness of the composite film 6 needs to be about 10 to 15 μm. Further, the thickness of the substrate of the liquid crystal element of the small screen is about 0.3 mm, but the thickness of the substrate used for the liquid crystal element of the large screen is about 2 mm. The chipping width W is larger as the liquid crystal element has a larger screen.

Therefore, in the conventional polymer-dispersed liquid crystal element, when the display is viewed from an oblique direction, all the lit pixels appear as pixels with a small width, one side of which is chipped off, resulting in a display failure. Brightness and contrast are reduced.

This also applies to the phase transition effect type liquid crystal element, and in this phase transition effect type liquid crystal element, the light incident on the region of the liquid crystal layer to which the electric field is applied is transmitted through the liquid crystal layer. Since the light incident on the non-electric field region is scattered in all directions in the liquid crystal layer, when the display is viewed obliquely, the width of the lit pixel appears small and the brightness and contrast of the display decrease.

Moreover, when the conventional light-scattering type liquid crystal element is manufactured by a method of bonding a pair of substrates after supplying a mixed solution of a polymer material and liquid crystal or liquid crystal onto one substrate,
There is also a problem that air bubbles are generated in the liquid crystal layer (liquid crystal / polymer composite film in the polymer dispersed liquid crystal element) or between the liquid crystal layer and the substrate, which causes display unevenness in the liquid crystal element.
Note that this problem is not limited to the light-scattering liquid crystal element of polymer dispersion type or phase transition effect type, and the same applies to other liquid crystal elements such as a TN type liquid crystal element.

That is, as a method of manufacturing a liquid crystal element, a method of filling a pair of substrates with a sealing material and then filling a liquid crystal between the substrates by a vacuum injection method, and supplying an appropriate amount of the liquid crystal on one substrate, There is a method of joining a pair of substrates after that, but the former manufacturing method has a problem that the manufacturing equipment cost is high because a large-scale vacuum injection device is required, and liquid crystal injection also takes time. .

In this regard, in the latter manufacturing method, since the liquid crystal is supplied onto one of the substrates before joining the pair of substrates, a liquid crystal layer is printed and an appropriate amount of the liquid crystal is printed on the one substrate. It can be easily formed by adding or dropping it, and thus the liquid crystal element can be manufactured at low cost.

However, in this manufacturing method, the liquid crystal is supplied onto one of the substrates, and the sealing material is printed on the other substrate along the outer peripheral edge thereof to bond the pair of substrates. When the two substrates are superposed, air is trapped between the substrates, and this air remains as bubbles in the liquid crystal layer or between the liquid crystal layer and the substrate, resulting in non-uniform electro-optical characteristics of the liquid crystal element. Display unevenness occurs.

The present invention is of a reflective type, but has a wide viewing angle which enables a high quality display close to the display quality when viewed from the front direction even when viewed from an oblique direction, and yet, on the other hand, No bubbles are generated in the liquid crystal layer or between the liquid crystal layer and the substrate even when the manufacturing method is such that a pair of substrates are joined after supplying a mixed solution of a polymer material and liquid crystal or liquid crystal onto the substrate. The object is to provide a light-scattering liquid crystal element.

[0028]

According to the present invention, a liquid crystal layer in which the alignment state of liquid crystal molecules is changed between a state in which transmitted light is scattered by an electric field and a state in which transmitted light is transmitted between a pair of front and back transparent substrates provided with transparent electrodes is provided. In the light-scattering liquid crystal element sandwiching the substrate, at least the back side substrate of the pair of transparent substrates is a flexible substrate made of a resin film, and a reflecting member is provided on the outer surface of the back side substrate. To do.

The present invention is applied to, for example, a polymer dispersion type liquid crystal element in which the liquid crystal layer is a liquid crystal / polymer composite film in which liquid crystal is dispersed in a polymer. Further, in the present invention, the reflecting member includes, for example, a reflecting film and a phosphor film provided on the upper surface of the reflecting film. Further, the reflecting member may be one in which a hard protective plate is provided on the lower surface of the reflecting film.

[0030]

In the light-scattering type liquid crystal element of the present invention, since the back side substrate is a flexible substrate made of a resin film, the thickness of the back side substrate can be made extremely thin. The distance from the surface of the layer (the surface in contact with the front-side substrate) to the reflecting member surface can be shortened.

If the distance from the surface of the liquid crystal layer to the surface of the reflecting member is short, the bright area (the area where the light transmitted through the liquid crystal layer is shining) and the field of view on the reflecting member when the display is viewed obliquely. Since the deviation from the area is small, the width of the display drop-off that occurs as a shadow due to light scattering in the liquid crystal layer on one side of the bright area is small, and therefore when viewed from an oblique direction, Since a high-quality display close to the display quality when viewed is obtained, the viewing angle becomes wide.

Moreover, in this liquid crystal element, since the back side substrate is a flexible substrate made of a resin film, a pair of substrates is prepared by supplying a mixed solution of a polymer material and liquid crystal or liquid crystal onto one substrate. In the case of manufacturing by the bonding method, the back side substrate can be bent in an arc shape and superposed on the front side substrate from one end side thereof. When the substrates are superposed in this manner, the air between the substrates is pushed out sequentially from one end side to the other end side as the substrates are superposed, so that the air is not trapped between the substrates.

Therefore, the liquid crystal element of the present invention is manufactured in a liquid crystal layer or a liquid crystal layer even if it is manufactured by a manufacturing method in which a mixed solution of a polymer material and liquid crystal or liquid crystal is supplied onto one substrate and then a pair of substrates is bonded. No air bubbles are created between the layer and the substrate.

In the liquid crystal device of the present invention, if the reflecting member is composed of a reflecting film and a phosphor film provided on the upper surface of the reflecting film, the light reflected by the reflecting film is the phosphor film. Since the colored light of high brightness is colored in the color of the fluorescence emitted by, the bright color display becomes possible.

Further, in the liquid crystal element of the present invention, the back side substrate is a flexible substrate made of a resin film, but the front side substrate is a hard substrate or a reflective film provided on the outer surface of the back side substrate. The strength of the liquid crystal element can be ensured by using a reflecting member provided with a hard protective plate on the lower surface, and the strength of the liquid crystal element can be improved by using a hard substrate as the front side substrate and also providing the protective plate. Can be higher.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a polymer dispersion type liquid crystal device will be described below with reference to the drawings. FIG. 1 is a sectional view of a polymer dispersed liquid crystal device showing a first embodiment of the present invention,
FIG. 2 is an enlarged view of a part thereof.

In this polymer-dispersed liquid crystal device, a pair of front and back transparent substrates 11 and 12 are bonded to each other via a frame-shaped sealing material 15 at their peripheral portions, and the sealing material 15 between the substrates 11 and 12 is used. A liquid crystal / polymer composite film 16 in which a liquid crystal is dispersed in a polymer is provided in the enclosed area, and the inner surfaces (opposite surfaces of the composite film 16) of both substrates 11 and 12 are Transparent electrodes 13 and 14 are formed.

This liquid crystal element is of a simple matrix type, for example, and the electrodes 14 of one substrate, for example, the back substrate 12 have a plurality of scanning electrodes formed in parallel with each other, and the other substrate, that is, the front surface. The electrode 13 of the side substrate 11
Is a plurality of signal electrodes formed so as to be orthogonal to the scanning electrodes 14.

The liquid crystal / polymer composite film 16 is one in which liquid crystal is dispersed in a polymer, and the composite film 16 is polymerized so as to have a gap like a sponge as shown in FIG. The liquid crystal 1 is placed in each gap of the polymer layer 16a.
It has a structure in which 6b is confined. In this embodiment, a nematic liquid crystal having a positive dielectric anisotropy is used as the liquid crystal 16b.

In this liquid crystal element, both substrates 1
Of the substrates 1 and 12, the front side substrate 11 is a hard substrate made of glass or the like, and the back side substrate 12 is a flexible substrate made of a transparent resin film such as PET (polyethylene terephthalate).

The front side substrate (hard substrate) 11
Is a board having a thickness (about 0.3 mm for a small-screen liquid crystal element and about 2 mm for a large-screen liquid crystal element) capable of ensuring strength against bending and twisting of the liquid crystal element. The thickness of the flexible substrate 12 is about 0.1 mm.

Further, this liquid crystal element is of a reflection type in which a reflection member 17 is arranged on the back surface thereof, and the reflection member 1
Reference numeral 7 includes a reflection film 17a made of a metal film such as an Al film or a white reflection film of Ba SO ₄ (barium sulfate), and a phosphor film 17b provided on the upper surface of the reflection film 17a. The reflective film 17a is deposited on the surface of the base sheet 19 made of a resin film or the like by vapor deposition or sputtering.

The fluorescent substance film 17b is made by mixing fine powdery fluorescent pigments in a dispersed state in a transparent resin, and the fluorescent substance film 17b has high brightness for the light reflected by the reflecting film 17a. It is provided to make the colored light.

The coloring of the light by the phosphor film 17b will be described. The light incident on the reflection member 17 reaches the reflection film 17a through the phosphor film 17b and reaches the reflection film 1a.
The light reflected by 7a is emitted again through the phosphor film 17b, and at this time, the light passing through the phosphor film 17b hits the fluorescent pigments scattered in the phosphor film 17b.

The fluorescent pigment transmits or reflects the light of a specific wavelength range, that is, the light of the same wavelength range as the fluorescent color emitted by the fluorescent pigment, out of the light hitting the fluorescent pigment, and transmits the light of other wavelength ranges. The light is absorbed, and the energy of the light emits light (fluorescence) in the specific wavelength range. The fluorescence emitted by the fluorescent pigment is emitted to the surroundings of the fluorescent pigment, of which the fluorescence toward the liquid crystal / polymer composite film 16 is emitted as it is, and the fluorescence toward the reflective film 17a is reflected by the reflective film 17a. The light is emitted to the composite film 16 side. This also applies to light transmitted or reflected by the fluorescent pigment.

Therefore, the reflected light from the reflecting member 17 is the light that has passed through the phosphor film 17b without hitting the fluorescent pigment, the fluorescence emitted by the fluorescent pigment, and the light that has been transmitted or reflected by the fluorescent pigment ( Light in the same wavelength range as the fluorescent color emitted by the fluorescent pigment). The color density of the reflected light is determined by the amount of the fluorescent pigment mixed in the phosphor film 17b.

Further, unlike the color filter, the phosphor film 17b does not transmit only light in a specific wavelength region of visible light and absorbs light in other wavelength regions to obtain colored light. The fluorescent pigment in the phosphor film 17b absorbs visible light and ultraviolet rays other than a specific wavelength range and absorbs light in the specific wavelength range by the energy of the light. Since it is emitted, the intensity of the light colored by the phosphor film 17b is much higher than the intensity of the colored light by the color filter. For this reason,
The light reflected by the reflecting member 17 becomes high-brightness colored light colored in the color of fluorescence emitted by the phosphor film 17b.

In this embodiment, the phosphor film 17 is used.
b, a region emitting red fluorescence (region containing a fluorescent pigment emitting red fluorescence), a region emitting green fluorescence (a region containing fluorescent pigment emitting green fluorescence), and a region emitting blue fluorescence (Areas in which a fluorescent pigment that emits blue-based fluorescence is mixed) are alternately formed corresponding to each pixel portion of the liquid crystal element.

In the polymer dispersed liquid crystal device of this embodiment, since the back side substrate 12 is a flexible substrate made of a resin film, the thickness of the back side substrate 12 is extremely thin (about 0. 1 mm), therefore, the distance from the surface of the liquid crystal / polymer composite film 16 (the surface in contact with the front surface side substrate 11) to the surface of the reflecting member 17 is short, so that the display dropout width when the display is viewed from an oblique direction is Get smaller.

That is, also in this liquid crystal element, when the display is viewed from an oblique direction (direction inclined with respect to the normal line of the liquid crystal element) as indicated by an arrow in FIG. 2, a bright region (on the reflecting member 17) Since the area A irradiated with light transmitted through the composite film 16 and the visual field area B are displaced as shown in the figure, one side of the bright area A, that is, the side opposite to the direction of displacement of the visual area B. Part becomes a shadow due to light scattering in the composite film 16 over a width W corresponding to the amount of deviation between the bright region A and the visual field region B, and only the region C of the bright region A is visible, and the illuminated pixel However, the shape becomes chipped off on one side.

Further, outside the other side of the bright area A on the reflecting member 17, a part of the area adjacent to the bright area A together with the above-mentioned lighting pixel is included in the bright area A and the visual field B. Although it can be seen over the width W corresponding to the amount of deviation from
Since this portion also has a shadow due to light scattering in the composite film 16, only the area C of the bright area A can be seen as a lighting pixel.

However, in the above-mentioned liquid crystal element, since the distance from the surface of the composite film 16 to the surface of the reflecting member 17 is short, the bright area A and the visual field area B on the reflecting member 17 when the display is viewed from an oblique direction. Is small, and therefore, the width W of the chipped portion of the display which becomes a shadow due to light scattering on the composite film 16 at one side of the bright region A is small.

Therefore, according to the above liquid crystal element, even when viewed from an oblique direction, a high-quality display close to the display quality when viewed from the front direction can be obtained. Will be significantly wider.

In this liquid crystal element, the reflecting member 1 is used.
Since the reflective film 17a of No. 7 is a color reflective film having a phosphor film 17b on its upper surface, bright color display is possible.

That is, the above-mentioned liquid crystal element has both substrates 1
The display is driven by applying an electric field between the electrodes 13 and 14 formed on the electrodes 1 and 12, but the liquid crystal of each liquid crystal portion (the portion where the liquid crystal is confined) dispersed in the liquid crystal / polymer composite film 16 The molecules are oriented in various directions when no electric field is applied, and in this state, the light passing through the composite film 16 is
Since the light is scattered by the interface between the liquid crystal portion and the polymer and the light scattering action of the liquid crystal portion, the display of the non-electric field portion becomes a white turbid display.

When an electric field higher than the threshold voltage of the liquid crystal is applied between the electrodes 13 and 14, the liquid crystal molecules in each liquid crystal portion are uniformly arranged so as to be substantially perpendicular to the surfaces of the substrates 11 and 12. However, since the light passing through the composite film 16 is transmitted with almost no light scattering effect, the display of the electric field applying section is performed by the reflecting member 1.
The light reflected by 7 is displayed, but the reflection film 17a of the reflection member 17 is a color reflection film on which a phosphor film 17b is provided. Therefore, the light reflected by the reflection film 17a is It is a high-intensity colored light that is colored in the color of fluorescence emitted by the phosphor film 17b, and therefore bright color display is possible.

In this embodiment, as described above,
Since the phosphor film 17b is formed by alternately forming a region emitting red fluorescence, a region emitting green fluorescence, and a region emitting blue fluorescence in correspondence with each pixel portion of the liquid crystal element, each pixel is formed. Multicolor display can be performed by coloring red, green and blue.

In addition, the liquid crystal element has the back side substrate 12
Is a flexible substrate made of a resin film, the back side substrate when the manufacturing method of joining a pair of substrates after supplying a mixed solution of a polymer material and liquid crystal or liquid crystal on one substrate, 12 can be bent in an arc shape and superposed on the front side substrate 11 from one end side thereof. If the substrates 11 and 12 are superposed in this manner, the substrate 1
Since the air between the substrates 1 and 12 is pushed out sequentially from one end side to the other end side with the superposition of the substrates,
No air is trapped between them.

That is, FIG. 3 shows an example in which the liquid crystal element of the above-mentioned embodiment is manufactured by the above-mentioned manufacturing method, and in this manufacturing method, the liquid crystal element is manufactured as follows. First, on one of the pair of substrates 11 and 12, for example, the front substrate 11 which is a hard substrate, a mixed solution 16 'of a polymer material and a liquid crystal which undergoes a polymerization reaction by light is required by screen printing or gravure printing. The thickness is applied and supplied, and the other substrate, that is, the back-side substrate 12 which is a flexible substrate, is coated with the sealing material 15 in a frame shape along the outer peripheral edge portion by screen printing or the like. As the material of the sealing material 15, for example, a polymer material which is polymerized by light is used.

Next, the back side substrate 12 is bent in an arc shape as shown in FIG. 3, and one end side of the back side substrate 12 is overlapped with one end side of the front side substrate 11 with the sealing material 15 interposed therebetween. The substrate 11 is pressed against the front-side substrate 11 side with a constant pressure by the pressure roller 20, and the pressure roller 20 is pressed against the front-side substrate 1.
By moving the one side from the one side to the other side, the back side substrate 12 is superposed on the front side substrate 11 from the one side.

When the substrates 11 and 12 are piled up in this manner, the sealing material 15 and the mixed solution 16 'are pressed from one end of the substrates 11 and 12 to a predetermined thickness, and the substrates 11 and 12 are Since the air between 12, especially the air on the uneven surface of the mixed solution 16 'is pushed out from one end side to the other end side by side with the superposition of the substrates, the air is not trapped between the substrates 11 and 12.

After this, one or both substrates 11, 1 are
The sealing material 1 is irradiated with light (ultraviolet rays) from the outer surface side of 2.
5, the polymer material of the mixed solution 16 'is photopolymerized to form the liquid crystal / polymer composite film 16, and then the reflection member 17 is attached to the outer surface of the rear substrate 12 to complete the liquid crystal element. .

The method of forming the liquid crystal / polymer composite film 16 is a method called a photopolymerization phase separation method, and when the mixed solution 16 'is irradiated with ultraviolet rays, the polymer material in a monomer or oligomer state. However, when the double bond is released, it becomes a radical, and radicals of adjacent molecules combine with each other to form a polymer. The composite film 16 in which the liquid crystal 16b is dispersed in the layer 16a is formed.

As described above, the liquid crystal device of the above-described embodiment is a manufacturing method capable of manufacturing the liquid crystal device at a low cost. After supplying the mixed solution 16 'of the polymer material and the liquid crystal onto one of the substrates, the pair of substrates is manufactured. Since air is not trapped between the substrates 11 and 12 even if the manufacturing method is such that the substrates 11 and 12 are joined together, the liquid crystal / polymer composite film 16 and the composite film 16 are
No bubbles are formed between the substrate and the substrates 11 and 12, and therefore, the electro-optical characteristics of the liquid crystal element are not nonuniform and display unevenness does not occur.

In the above-mentioned manufacturing method, the mixed solution 16 'is applied to the front substrate 11 which is a hard substrate, and the sealing material 15 is applied to the rear substrate 12 which is a flexible substrate. ′ And the coating substrate of the sealing material 15 may be reversed. Further, in the above-mentioned manufacturing method, after the substrates 11 and 12 are superposed on each other, the polymer material of the mixed solution 16 'is photopolymerized to form the liquid crystal / polymer composite film 16. The formation of the composite film 16 includes forming the substrate 11,
It may be performed before stacking 12.

Further, in the liquid crystal element of the above-mentioned embodiment, the back side substrate 12 is a flexible substrate made of a resin film, but the front side substrate 11 is a hard substrate having sufficient strength. Can be secured.

In the above embodiment, the back side substrate (flexible substrate) 12 has a thickness of about 0.1 mm, but the back side substrate 12 has a thickness of 0.05 to 0.25 mm. Desirably, the thickness may be 0.07 to 0.13 mm. If the thickness of the backside substrate 12 is within this range, the chipping width of the display can be made sufficiently small, and the tensile strength of the backside substrate 12 can be reduced. Can also be secured.

Further, in the above embodiment, the strength of the liquid crystal element is secured by the front surface side substrate 11, but the back surface of the reflective film 17 provided on the outer surface of the back surface side substrate 12 which is a flexible substrate is also hard. Providing the protective plate can increase the strength of the liquid crystal element.

That is, FIG. 4 is a cross-sectional view of a polymer dispersion type liquid crystal device showing a second embodiment of the present invention. In this embodiment, the reflection member 17 provided on the outer surface of the rear substrate 12 is
It is assumed that a hard protective plate 17c made of glass, a hard resin, a metal plate or the like is provided on the lower surface (rear surface of the base sheet 19) of the reflective film 17a having the phosphor film 17b on the upper surface, and the liquid crystal element is provided by the protective plate 17c. The back side of is reinforced.

The second embodiment is the same as the first embodiment described above.
Since the protective plate 18 is added to the liquid crystal element of the above embodiment, duplicate description will be omitted by attaching the same reference numerals to the drawings. However, as in this embodiment, the protective plate 1 is provided on the back surface of the reflective film 17.
When 7c is provided, the base sheet 17 of the reflective film 17a
The reflective film 17a may be formed on the surface of the protective plate 17c by omitting a.

When a hard protective plate 17c is provided on the back surface side of the liquid crystal element as in this embodiment, this protective plate 1 is used.
Since the strength of the liquid crystal element can be secured by 7c, not only the back side substrate 12 but also the front side substrate 11 may be a flexible substrate made of a resin film.

In the first and second embodiments described above, the reflecting film 17a of the reflecting member 17 is a color reflecting film having the phosphor film 17b on the upper surface thereof, but the reflecting member 17 does not reflect light. If the ratio is high, the phosphor film 17b may not be used.

The liquid crystal element of the above embodiment is a polymer dispersion type liquid crystal element having the liquid crystal / polymer composite film 16 formed by the photopolymerization phase separation method as the liquid crystal layer. It can be applied to a polymer dispersion type liquid crystal device in which a liquid crystal / polymer composite film in which the liquid crystal capsules are microencapsulated and dispersed in a polymer layer is used as a liquid crystal layer, and a homeotropic molecule is provided between a pair of substrates. It can also be applied to a phase-transition-effect type liquid crystal device in which a nematic phase of an array and a cholesteric phase having a helical molecular structure in which helix axes are oriented in various directions are provided with a liquid crystal layer that undergoes a phase transition by an electric field.

Further, although the liquid crystal element of the above embodiment is of the simple matrix type, the present invention provides the pixel electrode and its active element and the supply line of the address signal and the data signal on one substrate, and the other one. A liquid crystal element of an active matrix system in which a counter electrode facing the pixel electrode is provided on a substrate, or a segment electrode having a shape corresponding to a display pattern is provided on one substrate, and a common electrode facing the segment electrode is provided on the other substrate. It can also be applied to the provided segment display type liquid crystal element.

[0075]

The light-scattering type liquid crystal element of the present invention is a reflection type when the display is viewed from an oblique direction because the back side substrate is a flexible substrate made of a resin film. However, it has a wide viewing angle that can obtain a high-quality display close to the display quality when viewed from the front even when viewed from an oblique direction, and a mixed solution of a polymer material and a liquid crystal on one substrate. Alternatively, in the case of manufacturing by a method of joining a pair of substrates after supplying liquid crystal, the back side substrate can be bent in an arc shape and superposed on the front side substrate from one end side thereof, so that the liquid crystal layer No bubbles are generated between the liquid crystal layer and the substrate.

Further, in the liquid crystal device of the present invention, when the reflecting member is composed of the reflecting film and the phosphor film provided on the upper surface thereof, the light reflected by the reflecting member is not reflected by the phosphor film. Since the high-luminance colored light is colored in the color of emitted fluorescence, bright color display is possible.

Further, in the liquid crystal element of the present invention, the back side substrate is a flexible substrate made of a resin film, but the front side substrate is a hard substrate or the reflecting member is provided on the outer surface of the back side substrate. If a hard protective plate is provided on the lower surface of the reflective film, the strength of the liquid crystal element can be ensured, and if the front side substrate is a hard substrate and the protective plate is also provided, the liquid crystal element is provided. The strength of can be made higher.

[Brief description of drawings]

FIG. 1 is a sectional view of a polymer-dispersed liquid crystal element showing a first embodiment of the present invention.

FIG. 2 is an enlarged view of a part of FIG.

FIG. 3 is a diagram showing a method for producing a polymer dispersed liquid crystal element.

FIG. 4 is a cross-sectional view of a polymer dispersed liquid crystal element showing a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional polymer dispersion type liquid crystal element.

FIG. 6 is an enlarged view of a portion of FIG.

[Explanation of symbols]

 11 ... Front side substrate (hard substrate) 12 ... Back side substrate (flexible substrate) 13 ... Signal electrode 14 ... Scan electrode 16 ... Liquid crystal / polymer composite film 17 ... Reflective member 17a ... Reflective film 17b ... Phosphor film 17c … Protective plate

Claims (5)

[Claims] 1. A light-scattering liquid crystal in which a liquid crystal layer is sandwiched between a pair of front and back transparent substrates provided with transparent electrodes so that the alignment state of liquid crystal molecules changes between a state in which transmitted light is scattered and a state in which transmitted light is transmitted by an electric field. In the element, at least the back side substrate of the pair of transparent substrates is a flexible substrate made of a resin film, and a reflection member is provided on the outer surface of the back side substrate, which is a light scattering feature. Type liquid crystal element. 2. The light-scattering liquid crystal element according to claim 1, wherein the liquid crystal layer is a liquid crystal / polymer composite film in which a liquid crystal is dispersed in a polymer. 3. The light-scattering type liquid crystal element according to claim 1, wherein the reflecting member comprises a reflecting film and a phosphor film provided on the upper surface of the reflecting film. 4. The light-scattering type liquid crystal device according to claim 1, wherein the front substrate of the pair of transparent substrates is a hard substrate. 5. The light scattering device according to claim 1, wherein the reflecting member comprises a reflecting film and a hard protective plate provided on a lower surface of the reflecting film. Type liquid crystal element.