JP3209254B2 - Display / recording medium and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display / recording medium and a method for manufacturing the same.

[0002]

2. Description of the Related Art A portable information terminal that is small and portable has been developed. A liquid crystal display is used for displaying information of these terminals. A widely used liquid crystal display is a reflection type display using a super twisted nematic (STN) type liquid crystal of monochrome display. In the future, a color display will be essential for improving visibility and displaying full-color natural images. However, in order to colorize the current liquid crystal display, it is necessary to use a color filter, and the use of a reflection type cannot be practically used due to a reduction in light transmittance and a reduction in light use efficiency due to separation of three primary colors. There is a problem that lighting with a light is required, which increases power consumption, thickness, and weight, and is unsuitable for a portable terminal.

To solve this problem, it has been necessary to develop a reflective color display technology which does not require a color filter and has high light use efficiency. As a simple method of obtaining a reflective color display, a display material in which a cholesteric liquid crystal is dispersed in a polymer has been proposed (see PP Crucker (Cro
oker) and DK Yang, `` Polymer-dispersed chiral liqu
id crystal color display) ”, Appl. Phys. Lett., Vo
l. 57, p. 2529-2531, 1991).

This display material has a structure in which a chiral nematic (induced cholesteric) liquid crystal obtained by adding a chiral agent to a nematic liquid crystal having a negative dielectric anisotropy is dispersed in a polymer. Cholesteric) liquid crystal [PDCLC (polymer-dispersed c
hiral nematic (cholesteric) liquid crystal)].

Assuming that the shape of the dispersed liquid crystal is spherical (droplet), its operation will be described with reference to FIG.

The proposed display device is shown in FIG.
As shown in FIG. 2, a PDCLC layer 1 has a structure in which a transparent electrode 4 is formed and is sandwiched between a pair of substrates 5. The PDCLC layer 1 has a structure in which a liquid crystal droplet 2 is dispersed in a polymer 3. When no electric field is applied from the power source 6, the orientation of the liquid crystal in the liquid crystal droplet 1 is determined by the characteristics of the interface with the polymer, and does not become the selective reflection state shown in FIG. Become. In particular, when the refractive index difference Δn of the liquid crystal is small and the refractive index is close to the refractive index of the polymer, the incident light 7 is transmitted almost as it is and becomes a transparent state in which the transmitted light 8 is formed. However, when an electric field is applied as shown in (b), the major axis of the liquid crystal molecules in the liquid crystal droplet is in a direction perpendicular to the electric field, and the cholesteric liquid crystal has a helical structure in which the axis is oriented in the direction of the electric field. Therefore, a selective reflection state in which a specific wavelength determined by the helical pitch is reflected. When the electric field is removed, the orientation of the liquid crystal returns to the initial state. In this method, since light of a specific wavelength determined by the helical structure of the cholesteric liquid crystal is reflected, display devices having different reflection wavelengths are stacked,
By using one display device, a reflective color display can be realized.

On the other hand, there has been proposed a display / recording medium using PDCLC which can write in a selective reflection state or return to an original transparent state by heating and electric field control (K. Kato, K. Tanaka). , S. Tsuru and S. Sakai, "
Color Image Formation Using Polymer-Dispersed Chol
esteric Liquid Crystal ", Jpn. J. Appl. Phys., Vol.
32, p. 4600-4604). FIG. 11 shows the operation of the PDCLC shown here.

The basic structure of the display / recording medium is the same as FIG. 10 as shown in FIG. Initially, it is in a transparent state, but as shown in FIG. 4B, when it is cooled by applying an electric field after heating, it becomes a selective reflection state in which light of a specific wavelength is reflected. This state is maintained even when the electric field is removed as shown in FIG. However, as shown in FIGS. 3D and 3E, when the film is cooled without applying an electric field after heating, the film returns to the original transparent state. Heating and electric field control are performed for each display / recording medium having a different reflection wavelength, and these are stacked to form one display / recording medium, whereby a reflective color display can be realized. Note that the difference from the display / recording medium in FIG. 10 lies in the presence or absence of memory properties, which largely depends on materials such as liquid crystal and a polymer, and a manufacturing method.

Further, a P which can alternately switch between a selective reflection state and a transparent state depending on the frequency of an applied electric field.
A display / recording medium using DCLC has been proposed (Kato, Tanaka, Tsuru, "Reflective Color Display by Memory PDCLC", Proceedings of the IEICE Spring Conference 1994- C-559, p.5- 126). This P
FIG. 12 shows the operation of DCLC. The basic structure of the display / recording medium is the same as that of FIG. 10 as shown in FIG. When the high frequency electric field is applied from the HF power supply 61, the medium enters a selective reflection state in which light of a specific wavelength is reflected, as shown in FIG. This state is maintained even when the electric field is removed as shown in FIG. However,
As shown in (d) and (e), when a low-frequency electric field is applied from the LF power supply 62, the orientation of the liquid crystal is disturbed by the movement of ions, and the liquid crystal returns to the original transparent state. The reflection type color display can be realized by controlling the frequency of the applied electric field for each display / recording medium having a different reflection wavelength and stacking them to form one display / recording medium.

However, in the color display using the PDCLC, since the selective reflection characteristic based on the helical structure of the cholesteric liquid crystal is used, the reflection occurs only for the circularly polarized light in the rotation direction corresponding to the helical direction. That is, as shown in FIG. 13, assuming that the PDCLC has a property of reflecting right circularly polarized light, reflected light is limited to light of a specific wavelength in right circularly polarized light. At this time, all the left-handed circularly polarized light is transmitted, and therefore, there is a problem that the reflectance is limited to 50% at most.

In order to solve this problem, a medium having the same reflection wavelength but different directions of reflected circularly polarized light may be produced and laminated. However, if each medium is produced and laminated independently between substrates on which electrodes are formed, There is a problem that the number of surfaces causing reflection and the absorption of light increase, and the intensity of reflected light does not improve.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a display / recording medium free from the above-mentioned disadvantages and a method for manufacturing the same.

[0013]

According to the present invention, a cholesteric liquid crystal or a chiral nematic liquid crystal (hereinafter collectively referred to as "cholesteric liquid crystal") is dispersed in a polymer, and a selective reflection state for reflecting circularly polarized light having a specific wavelength and a reflection state are disclosed. A display / recording medium including a polymer-dispersed cholesteric liquid crystal (hereinafter, PDCLC) layer which can be alternately changed between a non-active state and a non-active state. between the layers and the respective viewing containing at least one layer of the second PDCLC layer that reflects circularly polarized light of the direction different from that, and the substrate and PDCLC layer, a plurality of PDC
Non-PDCLC layers may be present in all or some of the LC layers.
However, the non-PDCLC layer is made of only a photo-curable resin.
Or a layer comprising a polyimide film .

In order to obtain a multi-color display or a full-color display, a display / recording medium constituted by laminating the above-described display / recording mediums having different reflected wavelengths is used.

The method for producing the display / recording medium according to the present invention includes the following method.

(1) After forming a first PDCLC layer in which a cholesteric liquid crystal is dispersed in a polymer between the electrode side of the first substrate on which electrodes are formed and the third substrate, the third substrate is removed. Peeling step, the first P formed on the first substrate
A second PDC in which a cholesteric liquid crystal having a different direction of circularly polarized light reflected from the cholesteric liquid crystal is dispersed in a polymer between a DCLC layer and a second substrate on which electrodes are formed.
Forming an LC layer.

(2) A step of forming a first PDCLC layer in which a cholesteric liquid crystal is dispersed in a polymer on the electrode of the first substrate on which the electrode is formed, the first PDCLC layer of the first substrate Forming a second PDCLC layer in which a cholesteric liquid crystal having a different direction of circularly polarized light reflected from the cholesteric liquid crystal is dispersed in a polymer; and PDCLC
Laminating on a layer.

(3) A step of producing a first PDCLC layer in which a cholesteric liquid crystal is dispersed in a polymer, wherein a cholesteric liquid crystal having a direction of circularly polarized light different from that of the cholesteric liquid crystal is dispersed in the polymer. Second PDCL
Forming a C layer, forming a multilayer body including at least one or more of each of the first PDCLC layer and the second PDCLC layer, and sandwiching the multilayer body between a pair of substrates on which electrodes are formed. And a step.

(4) A step of forming a first PDCLC layer in which a cholesteric liquid crystal is dispersed in a polymer, and a cholesteric liquid crystal having a direction of circularly polarized light different from that of the cholesteric liquid crystal is reflected on the first PDCLC layer. Forming a second PDCLC layer in which is dispersed in a polymer, and sandwiching the first and second PDCLC layers between a pair of substrates on which electrodes are formed.

(5) A first PDCL in which a cholesteric liquid crystal is dispersed in a polymer on a first substrate on which electrodes are formed.
A step of forming a C layer, a second P in which a cholesteric liquid crystal having a direction of circularly polarized light reflected from the cholesteric liquid crystal dispersed in a polymer is dispersed on a second substrate on which an electrode is formed.
Forming a DCLC layer, the first substrate and the second step of the substrate align Ri stuck both PDCLC layers together, the method comprising the city.

In the present invention, the method of forming the PDCLC layer includes (A) heating a mixture of a prepolymer and a cholesteric liquid crystal, which are polymerized by heating or light irradiation, or polymerizing the prepolymer by irradiating light. The polymer is separated into liquid crystal and polymer by a phase separation method (PIPS: Polymerization induced phase sep
(B) a method of heating the thermoplastic polymer and the cholesteric liquid crystal which are dissolved when the temperature is increased, and lowering the temperature from the state where the cholesteric liquid crystal is uniformly dissolved in the thermoplastic polymer. Phase separation method by heat (TIPS: Th)
ermally induced phase separation),
(C) A method of dissolving a polymer and a liquid crystal in a solvent and separating the polymer and the liquid crystal with the evaporation of the solvent. The phase separation method (SIPS: Solvent induced phase separation) accompanying the evaporation of the solvent.
and (D) a method in which a polymer that does not dissolve the liquid crystal and a cholesteric liquid crystal are suspended to encapsulate the liquid crystal (Encapsulation). Among them,
The method (A) is preferable because it can be applied to all the methods (1) to (5). The methods (B) to (D) can be applied to the methods (2) to (5). Furthermore, the method (B) can be applied to the method (1) by using thermoplastic polymers having different melting temperatures.

[0022]

PDCLC has a structure in which cholesteric liquid crystal is dispersed in a polymer, as described above. Cholesteric liquid crystal has a spiral structure in which the major axis direction of liquid crystal molecules gradually changes in a spiral. Cholesteric liquid crystals exhibiting such properties naturally exist, but chiral nematic (induced cholesteric) liquid crystals obtained by adding a chiral agent that induces a helical structure to nematic liquid crystals are widely used because it is necessary to control the twist direction and helical pitch. I have. Therefore, in the present invention, this chiral nematic liquid crystal is referred to as a cholesteric liquid crystal.

Since a chiral agent generally has a pair of dextrorotatory and levorotatory isomers, a dextrorotatory or levorotatory chiral nematic liquid crystal can be prepared. PDCLC can also be prepared.

FIG. 1 shows an example of a display / recording medium according to the present invention. A dextrorotatory PDCLC layer 11 that selectively reflects only right circularly polarized light and a levorotary PDCLC layer 12 that selectively reflects only left circularly polarized light, while having the same wavelength, are disposed between a pair of substrates 5 on which a transparent electrode 4 is formed. It is a sandwiched structure. Since both circularly polarized lights can be reflected and sandwiched between a pair of substrates, the number of reflection surfaces and light absorption by the substrates and electrodes is reduced, and a high reflected light intensity can be obtained.

FIG. 2 shows another example of the display / recording medium according to the present invention. FIG. 2A shows a case where a non-PDCLC layer 20 is provided between the PDCLC layers 11 and 12. In the medium of FIG. 1, since the PDCLC layers are in direct contact with each other, cholesteric liquid crystals are mixed near the boundary, There is a possibility that the effect of the chiral agent is offset and the intensity of the reflected light is reduced, or the helical pitch is changed. However, this can be prevented.
The non-PDCLC layer 20 may be a layer formed independently, or may be a layer formed when separating a polymer and a liquid crystal in forming the PDCLC layer. The point is that it is only necessary to prevent the twisting force from being lost or the helical pitch from being changed by the mixing of the chiral agent, and any material that does not reduce the reflected light intensity in a layer having this effect can be used.

FIG. 2 (b) shows the transparent electrode 4 of the medium of FIG.
Non-PDCLC layer 2 between DCLC layers 11 and 12
1 and 22 have an effect of removing the intrusion of dirt from the electrode 4 and the substrate 5 and the influence of the surface condition.

FIG. 2C shows a configuration in which (a) and (b) are combined, and a PDCL is provided between the PDCLC layers 11 and 12.
The non-C layer 20 is provided with non-PDCLC layers 21 and 22 between the transparent electrode 4 and the PDCLC layers 11 and 12. Although this structure requires many manufacturing steps, the manufacturing yield is high, and the stability and reliability are further improved.

FIG. 2D shows a structure in which a plurality of dextrorotatory PDCLC layers 11 and a plurality of left-rotary PDCLC layers 12 are laminated. (E) shows PD on each contact surface of the PDCLC layer of (d).
This is a configuration in which a layer other than the CLC is interposed. Although not shown, in the configuration of (d) or (e), a layer other than PDCLC can be further provided between the substrate and the PDCLC layer as shown in (b). It goes without saying that the number of layers to be laminated and the combination method can be changed according to the purpose.

In order to perform multi-color or full-color display, as shown in FIG. 3, FIGS. 1 and 2 (a) to 2 (e)
Display / recording media with different selective reflection wavelengths
For example, the display / recording medium 200 for red reflection, the display / recording medium 102 for green reflection, and the display / recording medium 103 for blue reflection may be stacked to form the entire display / recording medium 200.

The liquid crystal used in the present invention is a nematic liquid crystal having a negative dielectric anisotropy, for example, "EN series" manufactured by Chisso, and E.I. “ZLI-2806”, “ZLI-4330”, “ZL” manufactured by Merck
I-3381 "and" ZLI-2585 "(each trade name) can be used.

As the chiral agent, any chiral agent can be used as long as the compound has an asymmetric carbon and induces optical rotation with respect to liquid crystal molecules. For example,
There are a cyanobiphenyl derivative, a bis-annealed derivative, an ester derivative and the like. Merc
“S / R-811” and “S / R-1011” manufactured by K Company, “CNL series” manufactured by Asahi Denka Kogyo KK, and the like can be used.

In the present invention, as the polymer used for forming PDCLC, various acrylic resins and NOA65 (trade name, No.
and various cationic polymers such as epoxy resins.

As the thermoplastic resin, polyvinyl butyral, polymethyl methacrylate (PMMA), polyvinyl formal (PVF), poly (diisopropyl fumarate) (Pdi-iPD) and the like can be used.

As the resin for encapsulation, polyvinyl alcohol (PVA), ammonium polyacrylate, gelatin and the like can be used.

In the present invention, the characteristics of the PDCLC layer are related to the mixing amount of the liquid crystal and the polymer, but do not have a specific value and change continuously. If the liquid crystal is small, the reflectance is low, and if the liquid crystal is too large, the fluidity increases. Therefore, it may be determined depending on the application and the required characteristics, and basically, a mixed amount of liquid crystal of several percent to a value close to 100% can be used.

As the substrate used in the present invention,
In addition to various glass substrates, polyvinyl chloride (PV
Polymer films such as C), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE), polyphenylene sulfide (PPS), and polyimide (PI) can be used.

As the transparent electrode, indium tin oxide (ITO), tin oxide (Nesa film), titanium oxide (TiO 2)
₂ ) Metal oxides or thin metal films such as those described above require aluminum, molybdenum, copper,
Metals such as gold and silver can be used.

[0038]

The following examples further illustrate the operation of the present invention.

Embodiment 1 FIG. 4 shows one method of manufacturing a display / recording medium according to the present invention. In this embodiment, the PIPS method was used.

First, as shown in (a), between a first substrate 51 having a transparent electrode 4 made of indium tin oxide (ITO) and a third substrate 53 having no electrode formed thereon.
For example, a nematic liquid crystal having a negative dielectric anisotropy to which a chiral agent for inducing dextrorotation is added (trade name: EN-3)
8, manufactured by Chisso Corporation (hereinafter referred to as dextro cholesteric liquid crystal) and a photo-curable resin (trade name: NOA65,
(Norland Co.) in a weight ratio of 1: 1. Next, as shown in (b), ultraviolet light 41 which causes polymerization of the photocurable resin is irradiated, and the resin and the liquid crystal are phase-separated to produce the dextrorotatory PDCLC layer 11.
The third substrate 53 was peeled off as shown in FIG. Next,
Second substrate 5 on which transparent electrode 4 is formed as shown in FIG.
2 and a liquid mixture having the same ratio of the above-mentioned liquid crystal to which a chiral agent for inducing levorotation is added (hereinafter referred to as a levorotatory cholesteric liquid crystal) and the above-mentioned photocurable resin, and irradiated with ultraviolet light 41 again. . As a result, as shown in (e), the dextrorotatory first PDCLC layer 11 and the levorotatory second PDCL
The medium structure shown in FIG. 1 was completed in which the C layer 12 was laminated and sandwiched between the substrates on which the transparent electrodes were formed.

When a voltage was applied to the electrode to set it in a selective reflection state, it was found that a higher reflected light intensity was obtained than when only a single PDCLC layer was used.

FIG. 5 shows a manufacturing method in which gap control is facilitated by using a spacer. A 10 μm plastic spacer 31 was used when preparing the dextrorotatory first PDCLC layer, and a 20 μm plastic spacer 32 was used when preparing the levorotatory second PDCLC layer. When a voltage was applied to the electrode to set it in a selective reflection state, it was found that the reflected light intensity was almost twice as high as that obtained with only a single PDCLC layer because the control accuracy of the film thickness was high.

It is important that the PDCLC layer does not adhere to the third substrate 53 by peeling off the third substrate 53 as shown in FIG. The photocurable resin includes an acrylic resin and an epoxy resin in addition to the above-described NOA65 polyenethiol resin. These resins have poor adhesion to polyethylene, polyethylene terephthalate, polypropylene, nylon, silicone rubber, fluorine-based resins, and the like. Therefore, these materials are transferred to the third substrate 53.
Or a substrate coated with these may be used as the third substrate. Here, Teflon or polyethylene terephthalate, which is a fluororesin, was used as the third substrate 53. Peeling was very easy. Note that it is not necessary to form an electrode on the third substrate 53.

In the above description, the polymer was formed by irradiation with light using a photocurable resin. However, it is apparent that a light curable resin that can be polymerized by heating may be used, and the light irradiation may be replaced by heating. The display / recording medium was produced in the same manner as described above by replacing the photocurable resin with, for example, light and a thermosetting resin (trade name: MultiCure 628, manufactured by Daimax Co.), and the same effect was obtained.

As shown in FIG. 2 (a), a PDCLC layer is formed between the first and second PDCLC layers only by a photocurable resin.
When the non-layer 21 was formed to a thickness of about 100 nm by the same method, the reflection intensity was improved. This is probably because the mutual diffusion of the chiral agent was reduced. In addition, as shown in FIG.
When polyimide films were used as the non-LC layers 21 and 22, it was found that the same reflection characteristics could be obtained with this structure.

The structure shown in FIGS. 2D and 2E can be formed by repeating the above manufacturing method.

In this embodiment, since the mixed liquid of the prepolymer and the cholesteric liquid crystal is sealed between the substrates, it is effective when a photocurable resin whose polymerization does not proceed due to oxygen in the atmosphere at the time of polymerization is used.

Embodiment 2 FIG. 6 shows another manufacturing method of the display / recording medium of the present invention. Here, an example using PIPS is shown. (A)
As shown in (1), a liquid mixture of, for example, the dextrorotatory cholesteric liquid crystal and the photocurable resin described in Example 1 is applied on the first substrate 51 on which the transparent electrode 4 is formed. Is applied. As a result,
As shown in (b), a dextrorotatory first PDCLC layer 11 is produced. Thereafter, as shown in (c), a mixture of the left-handed cholesteric liquid crystal and the photocurable resin is applied in the same ratio,
Irradiation with ultraviolet light 41 is performed again. Second PDCLC with levorotation
After the layer 12 was formed, a display / recording medium was formed by sandwiching the second substrate 52 having the transparent electrode formed thereon as shown in FIG. As described in Example 1, since the photocurable resin has a property (oxygen effect) that hardly cures in an atmosphere containing oxygen, the atmosphere during ultraviolet light irradiation was nitrogen.

When a voltage was applied to the electrode to make it a selective reflection state, there was an effect that a reflected light intensity almost twice that of the case of only a single PDCLC layer was obtained.

Also in this method, the same result was obtained when a thermosetting resin which polymerized by heating was used as in Example 1 and light irradiation was replaced by heating.

It is apparent that this method can also realize a method of controlling a gap by using a spacer, a method of using a non-PDCLC layer, and a structure using two or more PDCLC layers.

Embodiment 3 FIG. 7 shows another manufacturing method of the display / recording medium of the present invention. First, an example using PIPS will be described. (A)
As shown in FIG. 7, a liquid mixture of, for example, the dextrorotatory cholesteric liquid crystal and the photocurable resin described in the first embodiment is applied on the first substrate 51 on which the transparent electrode 4 is formed, and the dextrorotatory cholesteric liquid crystal is irradiated with ultraviolet rays. The first PDCLC layer 11 was produced. on the other hand,
As shown in (b), for example, a liquid mixture of the left-handed cholesteric liquid crystal and the photocurable resin described in Example 1 is applied on the second substrate 52 on which the transparent electrode 4 is formed, and the left-handed light is irradiated by ultraviolet irradiation. The second PDCLC layer 12 was produced.
Thereafter, to prepare a display and recording medium cemented Ri together as shown in (c).

When a voltage was applied to the electrode to make it into a selective reflection state, there was an effect that a reflected light intensity almost twice as high as that of a single PDCLC layer alone was obtained.

As in Examples 1 and 2, the same results were obtained by using a thermosetting resin which polymerized by heating and replacing light irradiation with heating.

Further, the PDCLC layers 11 and 12 can be formed by the SIPS method. For example, polyvinyl butyral (PVB) and the dextro or dextro cholesteric liquid crystal used in Example 1 are dissolved in chloroform,
After coating on the substrate, the solvent is removed by heating, and (a)
And to prepare a structure (b), or, combined Ri stuck.

Further, an encapsulation method can be applied. For example, an aqueous solution of polyvinyl alcohol (PVA) is mixed with the dextro or dextro cholesteric liquid crystal used in Example 1, the liquid crystal is encapsulated, and then coated and dried on a substrate, and (a) and (b) structure to produce a, or, combined Ri stuck <br/>.

Also in this method, a method of controlling a gap using a spacer and a method of using a layer other than PDCLC can be applied. It is clear that a structure using more than two PDCLC layers can be realized by combining with another method.

Embodiment 4 FIG. 8 shows another manufacturing method of the display / recording medium of the present invention. First, an example using PIPS will be described.

On a substrate that does not adhere to the PDCLC layer, for example, a mixed solution of the dextrorotatory cholesteric liquid crystal and the photocurable resin described in Example 1 is applied, irradiated with ultraviolet rays, and peeled off from the substrate, as shown in FIG. Dextrorotary first PDCLC
Layer 11 was produced. On the other hand, as shown in (b), a second PDCLC layer 12 with left-handed rotation was produced in the same manner. Thereafter, to prepare a (c), sandwiched in the display and recording medium between the substrates 51 and 52 to form a transparent electrode with matched Ri bonded to each other (d).

When a voltage was applied to the electrode and the electrode was set to the selective reflection state, there was an effect that a reflected light intensity almost twice as high as that of a single PDCLC layer alone was obtained.

Also, it can be manufactured by the method shown in FIG. That is, a liquid mixture of, for example, the dextrorotatory cholesteric liquid crystal and the photocurable resin described in Example 1 is applied to the substrate 53 that does not adhere to the PDCLC layer, and is irradiated with ultraviolet rays (a) to obtain the dextrorotatory first cholesteric liquid crystal. A PDCLC layer 11 was produced (b). Next, as shown in (c), a second PDCLC layer 12 with left-handed rotation was formed on the first PDCLC layer 11, and was peeled off from the substrate. Thereafter, a display / recording medium was manufactured by sandwiching the substrate between the substrates 51 and 52 on which the transparent electrodes were formed (d).

As in the previous examples, the same results were obtained by using a thermosetting resin that polymerizes by heating and replacing light irradiation with heating.

The PDCLC layers 11 and 12 can also be manufactured by the SIPS method. For example, polyvinyl butyral (PVB) and the dextro or dextro cholesteric liquid crystal used in Example 1 are dissolved in chloroform,
After coating on the substrate, the solvent was removed by heating, and FIG.
The structures (a) and (b) may be manufactured and bonded .

Further, an encapsulation method can be applied. For example, the aqueous solution of polyvinyl alcohol (PVA) and the dextro or dextro cholesteric liquid crystal used in Example 1 were stirred, the liquid crystal was encapsulated, then coated and dried on a substrate, and FIG. The structure of b) may be prepared and bonded .

In this method, a method of controlling a gap by using a spacer and a method of using a layer other than PDCLC can be applied. It is clear that a structure using more than two PDCLC layers can be easily realized.

As described above, the gist of the present invention is to eliminate a factor of laminating a dextrorotatory PDCLC layer and a levorotatory PDCLC layer to reflect both circularly polarized lights and restrict the reflectance.
An object of the present invention is to prevent the number of reflection surfaces and the increase in absorption by interposing a laminate between a pair of substrates.

The layers that reflect left and right circularly polarized light can be laminated only on a PD having a structure in which liquid crystal is dispersed and sealed in a polymer.
This is due to the use of CLC. Since only liquid cholesteric liquid crystals are mixed with each other, it is difficult to laminate them.

It is clear that the materials used for the polymer, liquid crystal, substrate, electrode and the like are not limited to those described in the above embodiments. Various combinations are also possible for the manufacturing method.

[0069]

As described above, according to the present invention,
Since the reflected light intensity of the device using the cholesteric liquid crystal spiral structure can be increased, there is an effect that a display / recording medium which is natural and has high visibility can be realized.

The helical pitch of the cholesteric liquid crystal (chiral nematic liquid crystal) can be changed very easily by the amount of the chiral agent to be added. Therefore, it is easy to produce and stack display and recording media in which each of the three primary colors has a reflection wavelength. There is an effect that a multi-color or full-color display can be obtained.

Further, regarding the manufacturing method, the method of irradiating a mixture of a photocurable prepolymer and a cholesteric liquid crystal with light by sandwiching the substrate between substrates makes it possible to use a prepolymer whose curing speed is reduced in the air due to the oxygen effect. Has the effect of doing

The method of successively forming the PDCLC layers on the substrate has a high degree of freedom in the layer structure, and has an effect that a complicated structure having more than two PDCLC layers can be manufactured. If a flexible sheet-like film is used for the substrate, the PDCLC layer can be continuously laminated, and the area can be increased.

[0073] On the other hand, in the method combining Ri bonded after forming the PDCLC layer to separate the substrate, by the manufacturing process at the time of PDCL
This has an effect of preventing the C layer from being dissolved and mixed with each other.

The method of forming a PDCLC layer into a film does not require a substrate at the time of preparation, so that by sandwiching the PDCLC layer between necessary substrates after the preparation, there is an effect that a display / recording medium having a different specification can be produced very easily. .

In particular, if the PDCLC layer is formed in a single film, an arbitrary layer configuration can be easily realized by combining films, and a display / recording medium having a layer configuration as required can be provided in a short period of time. effective.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of the structure of a display / recording medium according to the present invention.

FIG. 2 is a schematic sectional view showing another example of the structure of the display / recording medium according to the present invention.

FIG. 3 is a schematic diagram showing a configuration of a multi-color or full-color display / recording medium according to the present invention.

FIG. 4 is a schematic view showing steps of a method for manufacturing a display / recording medium according to the present invention.

FIG. 5 is a schematic view showing steps of another method for manufacturing a display / recording medium according to the present invention.

FIG. 6 is a schematic view showing steps of another method for manufacturing a display / recording medium according to the present invention.

FIG. 7 is a schematic view showing steps of another method for manufacturing a display / recording medium according to the present invention.

FIG. 8 is a schematic view showing steps of another method for manufacturing a display / recording medium according to the present invention.

FIG. 9 is a schematic view showing steps of another method for manufacturing a display / recording medium according to the present invention.

FIG. 10 is a schematic diagram showing the principle of display using a conventional PDCLC.

FIG. 11 is a schematic diagram showing a principle of display using another conventional PDCLC.

FIG. 12 is a schematic diagram showing a principle of display using another conventional PDCLC.

FIG. 13 is a diagram for explaining a problem of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PDCLC layer 11 Right-rotation first PDCLC layer 12 Left-rotation second PDCLC layer 2 Liquid crystal droplet 3 Polymer 4 Transparent electrode 5 Substrate 51 First substrate 52 Second substrate 53 Third substrate 6 Power supply Reference Signs List 61 HF power supply 62 LF power supply 7 Incident light 8 Transmitted light 9 Selective reflected light 20 Non-PDCLC layer 21 Non-PDCLC layer 22 Non-PDCLC layer 100 Display / recording medium 101 Red-reflective display / recording medium 102 Green-reflective display / recording medium 103 Blue reflective display / recording medium 200 Multi-color or full-color display / recording medium 31, 32 Spacer 41 Ultraviolet light

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-209425 (JP, A) JP-T-58-501631 (JP, A) JP-T-63-501512 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) G02F 1/1334 G02F 1/13 505 G02F 1/1347 G02F 1/137

Claims (11)

(57) [Claims] 1. A cholesteric liquid crystal or a chiral nematic liquid crystal (hereinafter collectively referred to as a cholesteric liquid crystal) dispersed in a polymer and alternately changed between a selective reflection state in which circular polarized light of a specific wavelength is reflected and a non-reflection state. Polymer-dispersed cholesteric liquid crystal (hereinafter referred to as PDCL)
C) A display / recording medium including a layer, wherein a first PDCLC layer for reflecting a certain circularly polarized light and a second PDC for reflecting a circularly polarized light having a different direction are provided between the substrates on which the electrodes are formed.
Each saw including at least one layer of LC layer, and between the substrate and the PDCLC layer, a plurality of PDCLC layers
A non-PDCLC layer is provided in whole or in part between the layers, and the non-PDCLC layer is a layer made of only a photocurable resin.
Or a display / recording medium characterized by being a layer made of a polyimide film . 2. The display according to claim 1, wherein the reflected wavelengths are different.
Display / recording characterized by stacking recording media
Medium. 3. An electrode formed on an electrode side of a first substrate on which an electrode is formed.
Cholesteric liquid crystal dispersed in polymer between three substrates
After the first PDCLC layer is formed, the third substrate is peeled off.
Separating the first PDCLC layer and the electrode formed on the first substrate
The cholesteric liquid crystal between the second substrate formed with
Cholesteric liquid crystal with different direction of reflected circularly polarized light
To form a second PDCLC layer in which is dispersed in a polymer
2. The method for manufacturing a display / recording medium according to claim 1, comprising the steps of: 4. The method according to claim 1 , wherein the first substrate has an electrode formed thereon.
First PD with cholesteric liquid crystal dispersed in polymer
Process for manufacturing the CLC layer, the first PDCLC layer of said first substrate, said correspondent
Choles with different direction of circularly polarized light reflected from teric liquid crystal
Second PDCLC with teric liquid crystal dispersed in polymer
Forming a layer, and forming a second substrate on which an electrode is formed on the second PDCLC layer.
2. The method according to claim 1, further comprising the step of:
A method for manufacturing a recording medium. 5. A cholesteric liquid crystal dispersed in a polymer.
Forming a first PDCL C layer, wherein the direction of circularly polarized light reflected from the cholesteric liquid crystal is different from that of the cholesteric liquid crystal.
Cholesteric liquid crystal dispersed in polymer
Forming a PDCLC layer, each of the first PDCLC layer and the second PDCLC layer;
Forming a multilayer body containing more than more even without, and the
Work to sandwich a multilayer body between a pair of substrates on which electrodes are formed
2. The method of manufacturing a display / recording medium according to claim 1, comprising:
Law. 6. A cholesteric liquid crystal dispersed in a polymer.
Forming a first PDCLC layer , wherein the cholesteric liquid crystal is provided on the first PDCLC layer.
Is a cholesteric liquid crystal with different directions of reflected circularly polarized light
Forming a second PDCLC layer dispersed in a polymer
Degree, the first and second PDCLC layer to form an electrode one
2. The method of manufacturing a display / recording medium according to claim 1, further comprising: interposing the substrate between a set of substrates . 7. A cholesteric electrode on a first substrate on which electrodes are formed.
PDCLC layer in which liquid crystal is dispersed in polymer
The step of producing the said cholesteric liquid crystal on a second substrate formed with electrodes
Cholesteric liquid crystal with different direction of reflected circularly polarized light
To form a second PDCLC layer in which is dispersed in a polymer
Step, bonding the first substrate and the second substrate together with both PDCLC layers
2. The method for manufacturing a display / recording medium according to claim 1, comprising a step of combining. 8. A polymer is produced by heating or irradiation with light.
The mixture of prepolymer and cholesteric liquid crystal.
Or irradiate light to separate the polymer and liquid crystal.
8. A method according to claim 3, wherein a PDCLC layer is formed.
The method described in. 9. A thermoplastic polymer that dissolves when the temperature is increased.
And cholesteric liquid crystal are heated to make the thermoplastic polymer uniform
From the state in which the cholesteric liquid crystal is dissolved,
To separate polymer and liquid crystal by lowering the
Write according to any one of claims 3-7 you produce C layer
Law. 10. A polymer and a liquid crystal are dissolved in a solvent.
Is separated into polymer and liquid crystal with evaporation of PDCLC layer
A method according to any one of claims 4 to 7 for making. 11. A cholesteric polymer and a polymer which does not dissolve liquid crystal.
Liquid crystal is suspended, and the liquid crystal is encapsulated to form a PDCL.
The method according to any one of claims 4 to 7, wherein a C layer is formed.
Law.