JP2005215657A - Method for manufacturing fiber element for image display, fiber element sheet for image display using the same, and image display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which is easy to manufacture using no complicated manufacturing stages and free of a problem such as a decrease in lightness resulting from color display for a display which has a liquid crystal material charged in light-transmissive tube/hollow fiber. <P>SOLUTION: In the method for manufacturing the fiber element for image display which has the liquid crystal material for display charged in the transparent hollow fiber, the transparent hollow fiber is manufactured by extruding a material for the transparent hollow fiber and the liquid crystal material from a nozzle at the same time. The liquid crystal material is a cholesteric liquid crystal or chiral nematic liquid crystal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention can be used as a display for a personal computer, a mobile phone, a mobile terminal, or the like, or an image display that can be used for a display body that can acquire information from the display and can carry it independently, such as electronic paper and digital books. The present invention relates to a fiber element manufacturing method, an image display fiber element sheet using the same, and an image display method.

  Conventionally, as image display technology called so-called electronic paper that can be rewritten repeatedly, technologies such as liquid crystal with memory properties, particle electrophoresis, display using insulating toner, rotation of colored particles, electrochromy, etc. are known. It has been. However, each of the methods has a problem that the manufacturing method is complicated, and it is impossible to achieve an inexpensive and high-quality image display.

  As a display using a liquid crystal having a memory property, for example, a display system using a nematic liquid crystal mixed with a chiral agent or a display system using a cholesteric liquid crystal has been proposed. These liquid crystals have the feature that the liquid crystal itself reflects external light using the principle of interference reflection that does not require a color filter or a deflecting plate.

  A liquid crystal containing a chiral agent becomes electrically bistable in a stabilized state by adding a small amount of polymer or an interface stabilized state in which an alignment film is deposited. In the state where no electric field is applied, the planar alignment is performed as shown in FIG. 6A, and the color light according to the helical pitch of the liquid crystal is selectively reflected. When a weak electric field is applied, the focal conic orientation shown in FIG. 6B is changed and light is transmitted. When the electric field is released in this state, the focal conic orientation is maintained. Furthermore, when a high electric field is applied, the homeotropic orientation shown in FIG. 6C is obtained, and the transparency further increases. However, when the electric field is released from this state, the orientation changes to the planar orientation. Thus, planar alignment and focal conic alignment can be selected by controlling the electric field (see, for example, Non-Patent Document 1).

  FIG. 7 shows three types of liquid crystal layers with different spiral pitches in the planar state, such as a liquid crystal layer that selectively reflects red, a liquid crystal layer that selectively reflects green, and a liquid crystal layer that selectively reflects blue. Coloring can be achieved by laminating the layers (for example, see Non-Patent Document 2). However, there is a drawback that the brightness and contrast of the display are lowered by stacking.

In addition, a display device having a structure in which a light-transmitting tube filled with a liquid crystal material is disposed between substrates has been proposed (for example, see Patent Document 1). This is a configuration in which tubes filled with a liquid crystal material are arranged in parallel, and has been proposed as a display device that has a uniform thickness and can prevent the entry of moisture, gas, and the like from the outside. As an example of a method for filling a light-transmitting tube with a liquid crystal material, the liquid crystal material is filled from one end to the other end of one or more tubes by pressure or a capillary phenomenon. A vacuum is applied from the other end of the tube, and a liquid crystal material is sucked from one end by a vacuum pressure. Alternatively, a method has been proposed in which a vacuum pressure is applied from the other end and the liquid crystal material is filled by pressure from the other end.
That is, a method has been proposed in which a light-transmitting tube is produced in the first stage and a liquid crystal material is filled in a fine tube in the second stage. Such a method has a problem that the manufacturing apparatus becomes complicated and the productivity is extremely poor.

  A display using particle electrophoresis has been proposed. In this method, a dispersion medium of charged particles is sandwiched between two electrodes and a voltage is applied between the electrodes to control the movement of the fine particles and change the optical reflection characteristics to display. FIG. 8 shows a schematic diagram thereof. The white charged fine particles dispersed in the solvent in which the blue dye is dissolved move to the electrode having the opposite charge, so that white / blue change can be shown (for example, see Non-Patent Document 3).

  There has been proposed a method in which an element in which a dispersion liquid in which white electrophoretic particles are dispersed in a blue liquid is sealed in a transparent hollow cylinder is sandwiched between electrodes to perform display (for example, see Patent Document 2 or 3). White electrophoretic particles and yellow colored insulating liquid sealed in transparent cylinder, white electrophoretic particles and magenta colored insulating liquid sealed in transparent cylinder, white electrophoretic particles and cyan colored insulating A method has also been proposed in which liquids sealed in transparent cylinders are arranged in parallel and colored.

  Furthermore, the structure which installs an electrode in the outer side of a transparent cylinder (for example, refer patent document 4), the structure which provides a convex protrusion inside a transparent cylinder, and provides a small chamber in a cylinder (for example, refer patent document 5). .) Has been proposed. As a method of enclosing the migrating particles and the insulating liquid in the transparent cylinder, the insulating liquid and the migrating particles are stirred in a suitable container, and one end of the transparent cylinder is put into the liquid while stirring and A method of filling while sucking, or a method of putting dried electrophoretic particles in a transparent cylinder and then filling an insulating liquid (for example, refer to Patent Document 3-5), and a transparent hollow cylinder in a chamber, A method has been proposed in which the chamber is evacuated and then the display liquid is introduced into the chamber to fill the hollow cylinder with the display liquid. That is, a method has been proposed in which a light-transmitting tube is produced in the first stage, and a fine tube is filled with the electrophoretic material in the second stage. Such a method has a problem that the manufacturing apparatus becomes complicated and the productivity is extremely poor.

From the above prior art, a display element in which liquid crystal or migrating particles are filled in a light-transmitting tube or hollow fiber has a problem that its manufacturing method is complicated and productivity is poor.
JP 49-96694 (first page, Fig. 1-2) JP 2003-222910 A JP 2000-330142 A JP 2001-125513 A JP 2000-352945 A The Imaging Society of Japan, Japan Hardcopy 2000 Proceedings, 2000, P89-92 The Imaging Society of Japan, Japan Hardcopy2000 Proceedings, 2000, P73-76 The latest technology of digital paper, CMC Corporation, 2001, P.19-37

  The object of the present invention is that, from the above situation, in a method of filling a light-transmitting hollow fiber with a liquid crystal material, it can be easily manufactured without going through a complicated process. It is an object of the present invention to provide a display element that does not have a problem such as a decrease in brightness.

As a result of intensive studies to achieve the above object, the present inventors have obtained an image display fiber element that is inexpensive and excellent in productivity by simultaneously extruding a liquid crystal material and a transparent hollow fiber material. As a result, the present invention was found. That is, the present invention includes the following inventions.
(1) In the method for manufacturing an image display fiber element in which a liquid crystal material for display is sealed in a transparent hollow fiber, the transparent hollow fiber material and the liquid crystal material are simultaneously extruded from a nozzle to produce a transparent hollow fiber. A method for manufacturing an image display fiber element.
(2) The method for producing a fiber element for image display according to item (1), wherein the liquid crystal material is cholesteric liquid crystal or chiral nematic liquid crystal.
(3) The transparent hollow fiber material is a polyester resin, polyolefin resin, acrylic resin, urethane resin, polystyrene resin, ABS resin, fluorine resin, silicon resin, nylon resin, vinyl chloride resin. The method for producing a fiber element for image display according to item (1) or (2), which is at least one selected from resins.
(4) A method for producing a fiber element for image display, characterized in that an end of a transparent hollow fiber in which a liquid crystal material for display is sealed in the transparent hollow fiber is sealed with a laser.
(5) The method for producing a fiber element for image display according to (4), wherein the transparent hollow fiber is cut and sealed with a laser.
(6) The method for producing a fiber element for image display according to (4) or (5), wherein the laser is at least one selected from a CO ₂ laser, a YAG laser, and a semiconductor laser.
(7) In the image display fiber element in which the liquid crystal material for display is sealed in the transparent hollow fiber, the inside of the transparent hollow fiber is divided into small rooms, and the liquid crystal material is sealed in each small room. A fiber element for image display, characterized by comprising:
(8) A fiber sheet for image display, wherein the fiber elements for image display according to any one of items (1) to (7) are arranged in a sheet form.
(9) A fiber sheet for image display, wherein the fiber elements for image display according to any one of items (1) to (9) are bonded together to form a sheet.
(10) An image display characterized in that a plurality of image display fiber elements displaying different color tones according to any one of items (1) to (9) are bonded together to form a sheet. Fiber sheet.
(11) An image display method comprising displaying different color tones by an electric field using the image display fiber element sheet according to item (10).

  Compared to the method for producing an image display fiber element of the present invention, there is no complicated process and the production becomes easy. Further, the image display fiber element does not require the use of a color filter or the like, and a display device having a simple configuration can be manufactured.

The present invention will be described in detail below.
FIG. 1 is an explanatory view showing a method for producing an image display fiber element and an image display fiber element of the present invention. The extrusion nozzle has a nozzle part 1 and a nozzle part 2. The nozzle part 1 is a part for extruding a liquid crystal material, and the nozzle part 2 is a part for extruding a transparent hollow fiber material. Using such a nozzle, it is extruded at the same time while being heated, and stretched to a predetermined diameter to be fiberized.

  In the present invention, the term hollow fiber is used. In general, the term “fiber” is a name meaning a thin and long form having a diameter of several hundred μm or less, but in the present invention, the diameter of the hollow fiber is not particularly limited. The transparent hollow fiber of the present invention includes a hollow tube having a diameter of 1 to 10 mm and a pipe having a diameter larger than that. The hollow fiber is appropriately selected depending on the application, and a hollow fiber having a diameter of about 20 μm to 3 mm is preferably used for display.

  It is necessary to seal the end of the fiber so that the liquid crystal material contained in the transparent hollow fiber does not leak or foreign matter is not mixed. For sealing, there is a method of dissolving the hollow fiber material by heating, etc., but it is preferable to use laser light in view of problems such as the sealing shape. Furthermore, it is a more preferable embodiment that the fiber is cut at the same time as the cutting with the laser beam.

  When a liquid crystal material is encapsulated in a normal transparent hollow fiber, a display defect may occur due to an alignment disorder of the liquid crystal material in the hollow fiber. In order to prevent this, a display defect can be reduced by providing a wall in the hollow fiber and dividing the fiber into minute rooms. As shown in FIG. 2, the display fiber is embossed. Or as shown in FIG. 3, a laser beam is irradiated to a hollow fiber inner wall, and a micro chamber can be produced. The interval between the walls forming each room is preferably about 10 μm to 3 mm.

  In order to process the fiber element for image display into a sheet shape, for example, the fibers are bundled with a device as shown in FIG. 4 to form a sheet. Image display fiber elements having different display colors, for example, (1) image display fiber elements displaying red color, (2) image display fiber elements displaying green color, and (3) image display displaying blue color The fiber element is unwound, coated with an adhesive, and dried to form a sheet. At this time, by arranging the image display fiber elements of different colors in a regular order and adhering them with an adhesive, the respective colors can be arranged in stripes. As an adhesion method, it is possible to heat-bond the fibers by bringing the image display fiber elements into contact with each other and heating them.

In order to obtain different display colors, for example, nematic liquid crystal can control the spiral pitch of liquid crystal by adding a chiral agent, and by changing the blending amount of chiral agent, the colors of red, blue and green can be changed. It is possible to prepare a liquid crystal to be displayed. By encapsulating these liquid crystals in transparent hollow fibers, an image display fiber element having desired reflection characteristics can be obtained.
In addition, as the adhesive between the fiber elements, generally known adhesives such as water-based adhesives, emulsion-based adhesives, and solvent-based adhesives are appropriately used, but solvent-based adhesives are preferably used. For example, adhesives such as urethane, epoxy, polyester, alkyd, amide, and acrylic can be used.

  Information can be entered, erased, and rewritten by arranging, for example, a device for applying an electric field in each part of the fiber sheet. A known means can be applied to the device for applying an electric field. When the electrode plate is installed on the fiber sheet, glass is generally used as the material of the upper electrode plate, but transparent plastic, such as polyethersulfone resin, polycarbonate resin, or acrylic-based polymethylmethacrylate or styrene-based Then, a styrene-acrylonitrile copolymer may be used. The electrode plate is preferably formed by depositing ITO. On the other hand, the electrode plate installed on the lower side is preferably made of an opaque electrode material such as metal. The liquid crystal in the focal conic state transmits light. In order to suppress reflection, it is preferable to use a black lower substrate that absorbs light.

The materials that can be used in the present invention will be described.
As the liquid crystal material, cholesteric liquid crystal or chiral nematic liquid crystal is preferably used. For example, a nematic liquid crystal having positive dielectric anisotropy is added with a liquid crystal in which an optically active 2-methylbutyl group, 2-methylbutoxy group, or 4-methylhexyl group is bonded as a terminal group called a chiral agent. By doing so, a liquid crystal displaying each color can be obtained. The helical pitch is determined by the amount of chiral agent added. Specifically, for a cyanobiphenyl-based nematic liquid crystal (for example, E8 manufactured by Merck), a right-turn chiral agent (for example, CB15 manufactured by Merck) is about 50%, 40%, 30% in mass ratio, respectively. When added to a certain extent, liquid crystals of blue reflection, green reflection and red reflection can be obtained. In order to align, it is preferable to add to these liquid crystals a polymer precursor capable of obtaining a refractive index substantially the same as that of the liquid crystals after polymerization, for example, NOA65 manufactured by Norland. In addition, spacer particles may be mixed with the liquid crystal material.

  The transparent hollow fiber is preferably highly transparent and excellent in laser processing suitability. Specific hollow fiber materials include polyester resins, polyolefin resins, acrylic resins, urethane resins, polystyrene resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), fluorine resins (for example, 4 Fluoroethylene resin), silicon resin, nylon resin, and vinyl chloride resin.

As the processing laser used in the present invention, a CO ₂ laser, an yttrium-aluminum-garnet crystal laser (YAG laser), and a semiconductor laser can be used. CO ₂ lasers are widely used for resin cutting and drilling because they are relatively inexpensive, have high output and are easy to handle. Since the oscillation wavelength is around 10.6 μm and there is almost no permeability to the material, it is suitable for cutting and sealing hollow fibers.
A YAG laser has a high light condensing property, can emit a short pulse with a high peak, and has an oscillation wavelength of around 1.06 μm. If the output is sufficiently increased, the hollow fiber can be cut, sealed and hollowed.

In addition, a semiconductor laser is an example of a laser that has not been as high as a CO ₂ laser or a YAG laser but has recently been used for processing. In general, elements having a plurality of wavelengths from an oscillation wavelength of about 810 nm to 980 nm are used, and a wavelength suitable for a target material can be selected. If the output is sufficiently increased, the hollow fiber can be cut, sealed and hollowed. Furthermore, the semiconductor laser is preferably used because the structure of the oscillator is simple and maintenance is easy.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “%” and “part” mean “% by mass” and “part by mass” unless otherwise specified.

Example 1
(1) Preparation of liquid crystal As a cholesteric liquid crystal of a display layer that selectively reflects red color light, 65 parts of nematic liquid crystal E48 (manufactured by Merck) having positive dielectric anisotropy, right-turning chiral agent CB15 (Merck Company) 35 parts) were mixed.
As the cholesteric liquid crystal of the display layer that selectively reflects green color light, 58 parts of nematic liquid crystal E48 (made by Merck) having positive dielectric anisotropy and 42 parts of right-turning chiral agent CB15 (made by Merck) are mixed. did.
As the cholesteric liquid crystal of the display layer that selectively reflects blue color light, 51 parts of nematic liquid crystal E48 (manufactured by Merck) having positive dielectric anisotropy and 49 parts of right-turn chiral agent CB15 (manufactured by Merck) are mixed. did.
To these cholesteric liquid crystals, 15 parts of thiol-based UV polymerized polymer precursor NOA65 (manufactured by Norland) was added.

(2) Fabrication of image display fiber element Using a base as shown in FIG. 1, a liquid crystal that selectively reflects red color light and PET, which is a hollow fiber material, are extruded to an inner diameter of 200 μm, and red. A fiber element for display was obtained.
Similarly, a liquid crystal that selectively reflects green color light and PET, which is a hollow fiber material, were extruded to have an inner diameter of 200 μm to obtain a green display fiber element.
Similarly, liquid crystal that selectively reflects blue color light and PET, which is a hollow fiber material, were extruded so as to have an inner diameter of 200 μm to obtain a blue display fiber element.
The produced fiber was irradiated with UV by a UV irradiation apparatus. Both ends of the fiber were melted and sealed by heating. Furthermore, the fiber was heated and embossed at a period of 2 mm to produce a small chamber in the fiber.

(3) Sheeting of image display fiber element Adhesives (trade name: BL-2, manufactured by Sekisui Chemical Co., Ltd.) of the above three image display fiber elements changing to different color tones in the order of red, green and blue. Was used to make a sheet.

(4) Display device formation As shown in FIG. 5, the display elements of yellow, magenta, and cyan were sandwiched so that the stripe-shaped ITO glass electrode having a width of 200 μm was orthogonal. A black sheet was pasted on the back side of the lower electrode. A power supply device was attached to each of three sets of electrodes so that an electric field could be applied independently for each of red, green, and blue.

(5) Evaluation By controlling the voltages of the upper electrode and the lower electrode, it was possible to display in any combination of colors such as red / black / black, green / black / black, and blue / black / black.

Example 2
(1) Preparation of liquid crystal As a cholesteric liquid crystal of a display layer that selectively reflects red color light, 65 parts of nematic liquid crystal E48 (manufactured by Merck) having positive dielectric anisotropy, right-turning chiral agent CB15 (Merck Company) 35 parts) were mixed.
As the cholesteric liquid crystal of the display layer that selectively reflects green color light, 58 parts of nematic liquid crystal E48 (made by Merck) having positive dielectric anisotropy and 42 parts of right-turning chiral agent CB15 (made by Merck) are mixed. did.
As the cholesteric liquid crystal of the display layer that selectively reflects blue color light, 51 parts of nematic liquid crystal E48 (manufactured by Merck) having positive dielectric anisotropy and 49 parts of right-turn chiral agent CB15 (manufactured by Merck) are mixed. did.
To these cholesteric liquid crystals, 15 parts of thiol-based UV polymerized polymer precursor NOA65 (manufactured by Norland) was added.

(2) Fabrication of image display fiber element Using a die as shown in FIG. 1, liquid crystal that selectively reflects red color light and PET, which is a hollow fiber material, are extruded to an inner diameter of 100 μm. A fiber element for display was obtained.
Similarly, a liquid crystal element that selectively reflects green color light and PET, which is a hollow fiber material, were extruded so as to have an inner diameter of 100 μm to obtain a green display fiber element.
Similarly, a liquid crystal that selectively reflects blue color light and PET, which is a hollow fiber material, were extruded to have an inner diameter of 100 μm to obtain a blue display fiber element.
The produced fiber was irradiated with UV by a UV irradiation apparatus. Both ends of the fiber were sealed with a semiconductor laser (trade name: UDL-15V, manufactured by Olympus Marketing Co., Ltd.) with 5 W output and 40 msec irradiation. Further, the inner wall of the tube was melted by laser irradiation of 3 W output and 20 msec at a period of 0.1 mm to form a wall, and a small chamber was produced in the tube.

(3) The same operation as in Example 1 was performed for forming the display fiber element into a sheet and forming a device.
(4) Evaluation performed the same operation as Example 1. However, a striped ITO electrode having a width of 100 μm was used. By controlling the voltage of the upper electrode and the lower electrode, it was possible to display in any combination of colors such as red / black / black, green / black / black, and blue / black / black.

  The fiber element for image display of the present invention does not have complicated production steps, is easy to manufacture, does not require the use of a color filter or the like, and can produce a display device having a simple configuration. Because of these advantages, there is a possibility of application in the field of flexible displays such as electronic paper.

The manufacturing method example of the fiber for a display of this invention. The example which embossed the display fiber of this invention, and divided the inside into the small room. An example in which the display fiber of the present invention is laser processed and the interior is divided into small rooms. The example of the method of making the display fiber of this invention into a sheet. 4 shows an example of a display device of the present invention. An explanatory diagram of the stable state of a liquid crystal with memory characteristics. Explanatory drawing of colorization method of liquid crystal with memory. Explanatory drawing of a display method using electrophoretic particles.

Claims (11)

  In the method for manufacturing an image display fiber element in which a liquid crystal material for display is enclosed in a transparent hollow fiber, the transparent hollow fiber material and the liquid crystal material are simultaneously extruded from a nozzle to produce a transparent hollow fiber. A manufacturing method of a fiber element for image display characterized.   The method for producing a fiber element for image display according to claim 1, wherein the liquid crystal material is cholesteric liquid crystal or chiral nematic liquid crystal.   The transparent hollow fiber material is selected from polyester resins, polyolefin resins, acrylic resins, urethane resins, polystyrene resins, ABS resins, fluorine resins, silicon resins, nylon resins, and vinyl chloride resins. The method for producing a fiber element for image display according to claim 1, wherein the fiber element is at least one kind.   A method for producing a fiber element for image display, characterized in that an end of a transparent hollow fiber in which a liquid crystal material for display is sealed in the transparent hollow fiber is sealed with a laser.   The manufacturing method of the fiber element for image displays of Claim 4 which cut | disconnects and seals the said transparent hollow fiber with a laser. The laser, CO ₂ laser, YAG laser, a manufacturing method of the image display fiber element according to claim 4 or 5 is at least one selected from a semiconductor laser.   In the image display fiber element in which the liquid crystal material for display is sealed in the transparent hollow fiber, the inside of the transparent hollow fiber is divided into small rooms, and the liquid crystal material is sealed in each small room. A characteristic fiber element for image display.   A fiber sheet for image display, wherein the fiber elements for image display according to claim 1 are arranged in a sheet form.   A fiber sheet for image display, wherein the fiber elements for image display according to claim 1 are bonded together to form a sheet.   A fiber sheet for image display according to claim 1, wherein a plurality of image display fiber elements displaying different color tones are bonded together to form a sheet. An image display method comprising displaying different color tones by an electric field using the image display fiber element sheet according to claim 10.

Images