JP2008065129A - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element, for which the occurrence of a short circuit is reduced, the weight is reduced, and which is highly reliable, in the liquid crystal display element which uses a liquid crystal layer containing liquid crystal droplets dispersed therein. <P>SOLUTION: The liquid crystal display element has at least two layers in between the liquid crystal layer, and an electrode layer arranged by coating or vapor deposition, wherein at least one layer thereof is a flat layer with 1μm or smaller unevenesses on the electrode-layer side surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display element, and more particularly to a liquid crystal display element having a liquid crystal layer in which liquid crystal is dispersed in a polymer resin.

  In recent years, research has been made on liquid crystal display elements having a liquid crystal layer in which liquid crystal is dispersed in a polymer resin (for example, Patent Documents 1 and 2). Since the liquid crystal layer has a structure in which liquid crystal droplets are dispersed in a polymer resin, the liquid crystal layer is flexible and has a characteristic that a displayed image does not change even when bent or pressed. In addition, since a plurality of liquid crystal layers can be directly stacked without using a substrate, it is suitable for multi-coloring. Note that since the liquid crystal layer can be formed by coating, a liquid crystal display element can be provided at low cost.

  In the above liquid crystal layer, when a chiral nematic liquid crystal material which is a rod-like molecule oriented in a spiral shape is used as the liquid crystal material, the spiral pitch is set to, for example, red, green, blue, because it has the property of selectively reflecting light matching the spiral pitch. Color display is possible when the wavelength is set to.

  Since this chiral nematic liquid crystal is bi-stable with no power supply, it can provide a display element with low power consumption because the planar state showing selective reflection and the focal conic orientation for transmitting light are bistable.

There is also known an element in which a liquid crystal dispersion in which the above chiral nematic liquid crystal is dispersed in a polymer is sandwiched between a pair of substrates with electrodes. By using such a dispersion, the orientation of the liquid crystal is hardly changed by an external pressure, and it is not a liquid, so that there are advantages such as easy handling.
US Pat. No. 6,585,849 US Pat. No. 6,690,447

  However, it is an element in which a liquid crystal layer in which droplets containing a liquid crystal material exhibiting a cholesteric phase are dispersed is sandwiched between electrodes using the prior arts of Patent Document 1 and Patent Document 2, and at least one side electrode is used for weight reduction. Application type electrodes such as silver paste have been used. At that time, it is necessary to provide a black absorption layer between the coating-type electrode and the liquid crystal layer. When an electrode was applied to the surface of the black absorption layer and a voltage was applied to the electrodes, there was a problem that partial short-circuiting (short circuit) frequently occurred between the electrodes.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly reliable liquid crystal display element that can reduce the short circuit and reduce the weight in a liquid crystal display element using a liquid crystal layer in which droplets are dispersed. It is said.

  This invention can achieve the said subject with the following structures.

1.
In a liquid crystal display element having, in this order, a liquid crystal layer in which droplets containing a liquid crystal composition are dispersed in a polymer resin and an electrode layer provided by coating or vapor deposition on a substrate provided with a conductive film.
A liquid crystal display element comprising at least two layers between the liquid crystal layer and the electrode layer, wherein at least one of the layers is a flat layer having a surface irregularity of 1 μm or less on the electrode layer side.

2.
2. The liquid crystal display element according to 1, wherein at least one of the two layers is a black absorption layer.

3.
3. The liquid crystal display element according to 1 or 2, wherein at least three layers are provided between the liquid crystal layer and the electrode layer.

4).
4. The liquid crystal display element according to claim 1, wherein at least one layer is provided between the conductive film and the liquid crystal layer.

5.
5. The liquid crystal display element according to any one of 1 to 4, wherein the liquid crystal composition exhibits a cholesteric phase at 20 ° C.

  According to the present invention, at least two layers are provided between the liquid crystal layer and the electrode layer provided by coating or vapor deposition, and the unevenness of the surface on the electrode layer side of at least one of the layers is a flat layer of 1 μm or less. Therefore, it is possible to provide a lightweight liquid crystal display element that can be driven satisfactorily without causing a short circuit between the conductive film and the electrode.

  Embodiments of the present invention will be described with reference to the drawings. Although specific sizes, materials, and the like have been described, these are merely examples, and the present invention is not limited thereto.

  FIG. 1 is a schematic cross-sectional view of a liquid crystal display element 1 according to the first embodiment of the present invention.

  A transparent first electrode 11 is formed of ITO (indium tin oxide) on a transparent PES (polyethersulfone) substrate 10. As the substrate 10, in addition to PES, a flexible transparent resin film such as polycarbonate (PC), polyethylene terephthalate (PET), polyarylate, or glass can be used. The first electrode 11 may be tin oxide other than ITO. The sheet resistance of the first electrode 11 is desirably 300Ω or less.

  An insulating layer 18 is formed on the first electrode 11. This insulating layer 18 is for preventing the short of the first electrode 11 and the influence of moisture on the electrode. The insulating layer 18 was coated with 1 μm of acrylate resin. As the insulating layer 18, in addition to the acrylate resin, an organic film such as methacrylate resin, epoxy resin, silicone resin, polyvinyl alcohol, polyethylene, polypropylene, and polyvinylidene chloride may be applied, or an inorganic film such as SiO2 or MgF2 is deposited. You may do it. The thickness of the insulating layer 18 is preferably 100 mm or more and 10 μm or less because there is an effect on short circuit and moisture permeation.

  A liquid crystal layer 13 is applied on the insulating layer 18. In the liquid crystal layer 13, liquid crystal droplets 15 are dispersed in a PVA binder 14. The liquid crystal used is a cholesteric liquid crystal having a selective reflection wavelength at 550 nm. For example, it was prepared by adding 14% by mass and 5.4% by mass of Merck's chiral materials CB15 and R1011 to a nematic liquid crystal BL006 manufactured by Merck. .

  A flat layer 16 is applied on the liquid crystal layer 13. The flat layer 16 is for forming a flat surface parallel to the first electrode 11 with the liquid crystal layer 13 interposed therebetween. Even if a voltage for driving liquid crystal is applied between the second electrode 17 formed on the flat layer 16 and the first electrode 11 by forming a flat surface parallel to the first electrode 11. Partial electric field concentration does not occur. Therefore, a good liquid crystal display element that is not short-circuited can be provided.

  The effect of the flat layer 16 will be described. When the liquid crystal layer 13 in which the liquid droplets are dispersed is formed, the surface of the liquid crystal layer 13 after the formation is in a rough state. For this reason, when the electrode layer 17 is formed thereon by coating or vapor deposition, the shape of the electrode layer 17 conforms to the surface roughness of the liquid crystal layer 13, and electric field concentration corresponding to the unevenness of the electrode layer 17 occurs. When the electric field concentrates, there is a problem that a short circuit occurs from that portion and the liquid crystal display cannot be performed. With respect to this problem, by forming the flat layer 16, the electrode layer 17 formed thereon by coating or vapor deposition can be flattened, and a short circuit can be prevented.

  The flatness of the flat layer 16 can be measured using a level difference measuring device. Specifically, using a surface profile measuring device Dektak 3030 manufactured by Nippon Vacuum Co., Ltd., the needle distance was 1 mg, the measurement distance 10 mm was measured three times, and the average value was measured as the unevenness value. The unevenness value is preferably 1 μm or less. If it exceeds 1 μm, a partial short circuit occurs when a driving voltage is applied to the liquid crystal display element.

  The flat layer 16 was formed by applying 1 μm of acrylate resin. As the flat layer 16, in addition to the acrylate resin, an organic film such as methacrylate resin, epoxy resin, silicone resin, polyvinyl alcohol, polyethylene, polypropylene, polyvinylidene chloride, or the like may be applied. Any material that can form a flat surface parallel to the first electrode 11 may be used. Further, the thickness of the flat layer 16 may be 0.5 μm or more and 5 μm or less, and if it is less than 0.5 μm, it is difficult to form a flat surface, and if it exceeds 5 μm, the electric field applied to the liquid crystal layer 13 becomes small. The voltage applied to the electrode 11 and the second electrode 17 must be increased, and the power supply becomes expensive.

  A black absorption layer 19 is preferably provided on the flat layer 16. As the black absorption layer 19, a black pigment such as carbon black dispersed in a resin can be used. By providing this black absorption layer 19, black display becomes possible. The application order of the black absorption layer 19 and the flat layer 16 may be reversed, and the flat layer 16 may be provided between the liquid crystal layer 13 and the electrode 17. The black absorbing layer 19 may be a flat layer, but it is difficult to flatten the surface roughness of the liquid crystal layer 13 because it contains a black pigment, and it is preferable to provide a separate flat layer 16.

  An insulating layer 18 is provided on the black absorption layer 19. The insulating layer 18 may have the same configuration as that of the insulating layer provided on the first electrode 11, and prevents a short circuit of the second electrode 17 formed on the insulating layer 18 and the influence of moisture. Is.

  In the present embodiment, the second electrode 17 uses a silver paste mixed with carbon black. In the present embodiment, a light-absorbing black silver paste is used as the second electrode 17, but light-transmitting ITO, tin oxide, or the like can also be used. As with the first electrode 11, the sheet resistance of the second electrode 17 is desirably 300Ω or less.

  A power source 20 for driving the liquid crystal display element 1 is connected to the first electrode 11 and the second electrode 17.

  The liquid crystal display element 1 was formed with the above configuration.

  Note that a protective layer may be provided over the second electrode 17. The protective layer is for protecting the second electrode 17 from moisture and mechanical shock, and it is desirable to form a light-absorbing member from the viewpoint of black display quality. Note that when a light-absorbing electrode or a protective layer is used for the second electrode 17, the black quality of the liquid crystal display element is affected, so that the reflectance is preferably 15% or less.

Next, the detail of the component which concerns on this invention is demonstrated.
(Liquid crystal layer)
The liquid crystal layer according to the present invention includes a binder made of a material having a hydroxyl group and a liquid crystal dispersed in the binder.
(Binder)
In the liquid crystal display device according to the present invention, a binder made of a material having a hydroxyl group is used, and specifically, the following binders are preferably used.

  Binders suitable in the present invention are transparent or translucent and generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film forming media such as gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, There are cellulose acetate, cellulose acetate butyrate, casein, starch, and cellulose esters.

Two or more of these binders may be used in combination, and the coating amount of the binder is preferably 100 g or less per m ² , and particularly preferably 20 g or less.

  The binder according to the present invention is important for securing the film strength of the dispersed liquid crystal-containing layer, particularly when the counter electrode is used. In order to make the film thickness constant together with the binder, a resin pillar structure or spacer particles are used. However, it is preferable not to use them because of simplification of the process.

  The polyvinyl alcohol preferably used in the embodiment according to the present invention includes, in addition to normal polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, cation-modified polyvinyl alcohol and anion-modified polyvinyl alcohol having an anionic group. Modified polyvinyl alcohol, polyvinyl alcohol derivatives, etc. are also included.

The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1000 or more, and particularly preferably has an average degree of polymerization of 1500 to 5000. The saponification degree is preferably 50 to 100%, particularly preferably 60 to 99.5%. Examples of the cation-modified polyvinyl alcohol have primary to tertiary amino groups and quaternary ammonium groups in the main chain or side chain of polyvinyl alcohol as described in JP-A No. 61-10383. Examples thereof include polyvinyl alcohol, which can be obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate. Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, N, N, N-trimethyl- (3-methacrylamideamidopropyl) ammonium chloride N- (1,1-dimethyl-3-dimethylaminopropyl) acrylamide and the like. The ratio of the cation-modified group-containing monomer in the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate. Examples of the anion-modified polyvinyl alcohol include polyvinyl alcohol having an anionic group as described in JP-A-1-206088, JP-A-61-237681 and JP-A-63-307979. Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265. Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. The block copolymer of the vinyl compound and vinyl alcohol which have the described hydrophobic group is mentioned. Polyvinyl alcohol can be used in combination of two or more different degrees of polymerization and different types of modification.
(liquid crystal)
As the liquid crystal according to the present invention (hereinafter also referred to as a liquid crystal composition), a nematic liquid crystal composition, a smectic liquid crystal composition, a liquid crystal composition exhibiting a cholesteric phase, or the like is used, and particularly includes a liquid crystal composition exhibiting a cholesteric phase. It is preferable.

  A chiral nematic liquid crystal is a typical liquid crystal exhibiting a cholesteric phase, and can be obtained by adding a predetermined amount of a chiral material to a nematic liquid crystal. This chiral nematic liquid crystal generally has a twisted arrangement of rod-like liquid crystal molecules and exhibits a cholesteric phase. When light is incident on this liquid crystal, when light is incident from a direction parallel to the helical axis, light having a wavelength represented by λ = np is selectively reflected (planar state). Here, λ is the wavelength, n is the average refractive index of the liquid crystal molecules, and p is the distance at which the liquid crystal molecules are twisted 360 °. On the other hand, when light is incident from a direction perpendicular to the helical axis, the light is transmitted without being reflected (focal conic state). Display is performed using this selective reflection and transmission.

  The operation mode of the reflective liquid crystal display having a memory property is disclosed in the technical paper SID International Symposium Digest of Technical Paper, Vol. 29, page 897. This operation mode is a method of performing display by switching the alignment state of the chiral nematic liquid crystal to either a planar state (light selective reflection state) or a focal conic state (light transmission state). Since the planar state and the focal conic state are stable states, once the liquid crystal is set to any state, the state is maintained semipermanently unless an external force is applied. In other words, it is useful as a reflective liquid crystal display element having a memory property that once an image is displayed, the displayed image is maintained as it is even when the power is turned off.

  The liquid crystal composition used in the present invention can be used in a state of being encapsulated in microcapsules.

  As a method for producing a microcapsule that can be used in the present invention, a known method such as a coacervation method, an interfacial polymerization method, or an in-situ method can be used. Among these, the production method by the coacervation method can be preferably used with little chemical influence on the liquid crystal composition which is an oil phase.

  The interfacial polymerization method can form a microcapsule wall by polymerizing polyamine, polyhydric phenol and the like with a polybasic acid halide, polyisocyanate and the like at the interface between the aqueous phase and the oil phase.

  As an in-situ polymerization method, microcapsules can be formed by crosslinking amide resin, phenol resin alone or a copolymer thereof used for urea-melamine or the like with formaldehyde or glutaraldehyde.

  On the microcapsule wall, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyvinyl alcohol, polyethylene oxide, polypropylene oxide, ethylene-vinyl alcohol copolymer, polyacetal , Acrylic resin, methylcellulose, ethylcellulose, phenolic resin, fluororesin, silicone resin, diene resin, polystyrene-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyphenylene ether, polyphenylene sulfide, Polyethersulfone, polyetherketone, polyarylate, aramid, polyimide, poly- -Microcapsule wall strength is improved by coexisting -phenylene, poly-p-xylene, poly-p-phenylene vinylene, polyhydantoin, polyparabanic acid, polybenzimidazole, polybenzothiazole, polybenzoxadiazole, polyquinoxaline, etc. Can be improved.

  Uniform particle size of the microcapsule particles according to the present invention can be achieved by taking out the microcapsule particles from the coating solution, drying and classifying them.

  Examples of the drying method include a method using a drying method such as a spray dryer, a rotary dryer, a band dryer, etc. Among them, the spray dryer or the rotary dryer has a high speed of drying, and at the same time the drying, It is preferable because it can be coated and has less microcapsule aggregation after drying. The spray dryer is one in which the microcapsules are ejected from a nozzle and dried by mixing droplets containing the microcapsules and hot air, and a commercially available spray dryer can be suitably used.

  A rotary dryer supplies capsules into a cylindrical dryer body and rotates the drying chamber itself or by rotating a stirring screw, and is commercially available from, for example, Daiwa Sanko Seisakusho Co., Ltd. ing.

  Examples of the classification method of the present invention include a specific gravity method, a sieving method, and the like, and the specific gravity method is preferable in that a broken microcapsule can be removed. As the specific gravity method, there is an air flow classification method, which is a method in which dried microcapsules are stirred with wind force and classified by an effect such as centrifugal force. It is commercially available from Nippon Pneumatic Industry Co., Ltd. and Seishin Corporation, and can be used preferably.

After classification and drying, the coating solution may be prepared by dispersing again in an aqueous solution (aqueous phase) in which the binder resin is dissolved.
(electrode)
In the liquid crystal display element according to the present invention, a pair of electrodes, at least one of which is translucent, is used.

  Of the pair of electrodes, at least one is preferably a metal electrode. As the metal electrode, for example, known metal species such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth, and alloys thereof can be used. As an electrode manufacturing method, an existing method such as a vapor deposition method, a printing method, an ink jet method, a spin coating method, a CVD method, or an atmospheric pressure plasma method can be used.

  The translucent electrode according to the present invention is not particularly limited as long as it is transparent and conducts electricity. Examples thereof include Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Tin Oxide (FTO), Indium Oxide, Zinc Oxide, and BSO (Bismuth Silicon Oxide). In order to form the electrode in this manner, for example, an ITO film may be vapor-deposited on the substrate by a sputtering method or the like, or an ITO film may be formed on the entire surface and then patterned by a photolithography method. The surface resistance value is preferably 300Ω / □ or less. The thickness of the transparent electrode is not particularly limited, but is generally 0.1 to 20 μm.

  The electrode pattern is formed using a known method such as a lithography method, a laser etching method, an electrostatic induction ink jet method, a dipping method, a spinner method, a spray method, a roll coater method, a flexographic printing method, and a screen printing method. can do.

  Next, the display operation of the liquid crystal display element 1 will be described. In the liquid crystal display element of the present embodiment, when the first threshold voltage for untwisting the liquid crystal exhibiting a cholesteric phase is Vth1, the voltage is smaller than the first threshold voltage Vth1 after the voltage Vth1 is applied for a sufficient time. When it is suddenly lowered to the second threshold voltage Vth2 or less, a planar state is entered. Further, when a voltage not lower than Vth2 and not higher than Vth1 is applied for a sufficient time, a focal conic state is established. These two states are stably maintained even after the voltage application is stopped (has a memory property). Further, by applying a voltage between Vth1 and Vth2, the planar state and the focal conic state can be mixed in a microscopic state, and halftone display, that is, gradation display is possible.

  Specifically, when a pulse voltage having a pulse width of 5 ms and a voltage of 140 V is applied between the first electrode 11 and the second electrode 17 of the liquid crystal display element 1, the liquid crystal phase of the liquid crystal droplet 15 exhibits a planar state, and light having a wavelength of 550 nm. Reflect. Therefore, when the liquid crystal display element 1 is observed from the substrate 10 side, green is displayed. Next, when a pulse voltage having a pulse width of 5 ms and a voltage of 80 V is applied between the first and second electrodes, the liquid crystal phase of the liquid crystal droplet 15 exhibits a focal conic state, and the light incident from the substrate 10 side is the liquid crystal layer 13. And is absorbed by the black absorption layer 19 and the second electrode 17. Therefore, the liquid crystal display element 1 shows black when observed from the substrate 10 side.

  In this embodiment, the selective reflection wavelength of the liquid crystal material is in the visible range, but the selective reflection wavelength is not limited to this. For example, selective reflection enables display by scattering and transmission of a liquid crystal layer when the wavelength is in the infrared region.

  Further, in the present embodiment, the configuration of the liquid crystal display element 1 is as described above, but the present invention is not limited thereto, and as a second embodiment, for example, as shown in FIG. The structure of the liquid crystal display element 2 created similarly to the first embodiment may be used except that the black absorption layer 19 is replaced.

  Specific examples and comparative examples are shown below together with the evaluation results.

As a first electrode and a second electrode of the following liquid crystal display element, full-surface electrodes that uniformly cover the element surface were used. In addition, the reliability evaluation method alternately applies a pulse voltage having a pulse width of 5 ms and a voltage of 140 V and a pulse voltage having a pulse width of 5 ms and a voltage of 80 V as an evaluation voltage between the first electrode and the second electrode. Then, the display state of the liquid crystal display element was evaluated.
(Example 1)
83 parts by weight of nematic liquid crystal (BL006; manufactured by Merck), 14 parts by weight of chiral material CB15 and 5.4 parts by weight of chiral agent R1011 (both manufactured by Merck) are mixed to selectively reflect light with a wavelength of 550 nm. Nematic liquid crystal A was obtained.

  An oil phase composition was prepared by dissolving 10 parts by mass of this liquid crystal A and 1 part by mass of Takenate D-110N (produced by Mitsui Takeda Chemical Co., Ltd.) as a polyvalent isocyanate in 100 parts by mass of ethyl acetate. This was put into a 1% polyvinyl alcohol aqueous solution and stirred and dispersed with a mixer to prepare an emulsion of about 8 μm.

  This was heated at 60 ° C. with stirring for 3 hours to prepare a microcapsule, which was used as a coating solution.

  A PES substrate having an ITO film formed on the entire surface was used as the substrate, and the ITO film was used as the first electrode. The liquid crystal display element was produced in the same manner as in the second embodiment except that an insulating layer was not provided. First, a microcapsule layer is bar-coated on ITO to a thickness of about 2 μm, and a black absorption layer (a mixture of carbon black and 10% PVA aqueous solution) is applied thereon to a thickness of about 1 μm. As a layer, a 10% PVA aqueous solution (PVA224 manufactured by Kuraray Co., Ltd.) was bar-coated to a thickness of about 3 μm. The unevenness on the surface of the flat layer at this time was 0.5 μm as a result of measurement by the method shown in the first embodiment. On this flat layer, a silver paste (DW-250H-5 manufactured by Toyobo Co., Ltd.) was formed by screen printing as a coating electrode as the second electrode. Even when the test voltage was applied to the liquid crystal display device thus produced, no short circuit was observed.

In this way, it was possible to produce a light-duty liquid crystal display element that can be driven satisfactorily without using a short-circuit between electrodes by using a coating-type electrode.
(Comparative Example 1)
As Comparative Example 1, a liquid crystal display element was produced in the same manner as in Example 1 except that the flat layer was not formed and the black absorbing layer was formed after the second electrode was applied. When the planarity of the surface was measured after forming the liquid crystal layer, the irregularities were 1.5 μm. When the test voltage was applied to the prepared liquid crystal display element, a short circuit was observed and the element could not be driven. This is presumably because the unevenness of the coating electrode is large due to the large unevenness of the liquid crystal display element, and the electric field is partially concentrated.
(Comparative Example 2)
As Comparative Example 2, a liquid crystal display element was produced in the same manner as in Example 1 except that no flat layer was formed. When the flatness of the surface was measured after forming the black absorption layer, the unevenness was 1.2 μm. When the test voltage was applied to the prepared liquid crystal display element, a short circuit was observed and the element could not be driven. This is presumably because the unevenness of the coating electrode is large due to the large unevenness of the liquid crystal display element, and the electric field is partially concentrated.
(Example 2)
As Example 2, a liquid crystal display element was produced in the same manner as Example 1 except that an insulating layer was provided between the ITO electrode and the μ capsule. The unevenness of the surface of the flat layer was 0.5 μm as in Example 1.

Even when a test voltage was applied to the liquid crystal display element, no short circuit was observed. In this way, a light-emitting liquid crystal display element that can be driven satisfactorily without the occurrence of a short circuit between the electrodes can be produced using the coating-type electrode.
(Example 3)
Example 3 was produced in the same manner as Example 1 except that the second electrode was produced by vapor deposition. At this time, the unevenness of the surface of the flat layer was 0.5 μm. On this flat layer, gold was vacuum-deposited using a vacuum deposition apparatus at a degree of vacuum of 10-5 Pa, and used as a second electrode.

Even when a test voltage was applied to the liquid crystal display element, no short circuit was observed. In this way, a light-emitting liquid crystal display element that can be driven satisfactorily without the occurrence of a short circuit between the electrodes can be produced using the coating-type electrode.
Example 4
Example 4 was prepared in the same manner as Example 1 except that the flat layer and the black absorbing layer were replaced and the order was reversed.

Even when a test voltage was applied to the liquid crystal display element, no short circuit was observed. In this way, a light-emitting liquid crystal display element that can be driven satisfactorily without the occurrence of a short circuit between the electrodes can be produced using the coating-type electrode.
(Example 5)
In Example 5, it produced similarly to Example 1 except having used BL006 (made by Merck Ltd.) for liquid crystal material.

Even when a test voltage was applied to the liquid crystal display element, no short circuit was observed. In this way, a light-emitting liquid crystal display element that can be driven satisfactorily without the occurrence of a short circuit between the electrodes can be produced using the coating-type electrode.
(Example 6)
In Example 6, a liquid crystal display device was produced in the same manner as in Example 1 except that the microcapsule layer was changed to 2.5 μm. The unevenness of the surface of the flat layer was 1.0 μm.

  Even when a test voltage was applied to the liquid crystal display element, no short circuit was observed. In this way, a light-emitting liquid crystal display element that can be driven satisfactorily without the occurrence of a short circuit between the electrodes can be produced using the coating-type electrode.

It is a schematic diagram of the cross section of the liquid crystal display element which concerns on the 1st Embodiment of this invention. It is a schematic diagram of the cross section of the liquid crystal display element which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 10 Board | substrate 11 1st electrode 13 Liquid crystal layer 14 Binder 15 Liquid crystal droplet 16 Flat layer 17 2nd electrode 18 Insulating layer 19 Black absorption layer 20 Power supply

Claims (5)

In a liquid crystal display element having, in this order, a liquid crystal layer in which droplets containing a liquid crystal composition are dispersed in a polymer resin and an electrode layer provided by coating or vapor deposition on a substrate provided with a conductive film.
A liquid crystal display element comprising at least two layers between the liquid crystal layer and the electrode layer, wherein at least one of the layers is a flat layer having a surface irregularity of 1 μm or less on the electrode layer side. The liquid crystal display element according to claim 1, wherein at least one of the two layers is a black absorption layer. The liquid crystal display element according to claim 1, wherein at least three layers are provided between the liquid crystal layer and the electrode layer. 4. The liquid crystal display element according to claim 1, wherein at least one layer is provided between the conductive film and the liquid crystal layer. 5. 5. The liquid crystal display element according to claim 1, wherein the liquid crystal composition exhibits a cholesteric phase at 20 ° C. 6.

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