JP2007322508A - Manufacturing method of optical modulation element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical modulation element that can be bent at a small curvature. <P>SOLUTION: The manufacturing method of an optical modulation element includes a member forming step to form a front face member, wherein a transparent electrode 111, a non-conductive transparent protective film 121, and a transparent orientation film 131 are laminated on a transparent synthetic resin film 101, and to form a rear-face member wherein an electrode 112 is laminated on a synthetic resin film 102; a projected structure forming step for forming a projected structure 14 in the inside of and along the upper side of an electrode face of the synthetic resin film 101; a cell-generating step for generating a bag-like cell 10 by making the synthetic resin film 102 and the electrode made to face each other, and bonding them after applying an adhesive 15 along both the sides and the lower side of the electrode of the synthetic resin film 101; a liquid crystal injection step for injecting liquid crystal into the cell 10; a pressing and extending step for depressing the cell 10, to press and extend the liquid crystal in the cell to a uniform thickness; and a sealing step for sealing the cell 10 by applying a sealant 17 outside the projected structure 14 of the cell 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a light modulation element, and more particularly to a method for manufacturing a light modulation element having flexibility.

  In recent years, various types of liquid crystal modulation elements, organic EL (electroluminescence), electronic ink, and the like have been proposed as flexible display devices.

  In particular, a display device using a liquid crystal modulation element can be applied not only to a transmission type, a reflection type, and a semi-transmission type, but also to display various images from moving images to still images. Therefore, it is considered a powerful display device.

  A liquid crystal modulation element applied to a flexible display device has a configuration in which a liquid crystal having a certain thickness is sandwiched between cells in which two flexible film substrates are bonded.

  As a method for injecting liquid crystal into a cell in which two substrates are bonded, a vacuum injection method and a one-drop fill method are known, but when the substrate has flexibility, the thickness of the liquid crystal is made constant. It was difficult.

  In order to solve the above problems, a method of manufacturing a liquid crystal display element capable of keeping the thickness of the liquid crystal constant even when a film cell is used has been proposed (for example, see Patent Document 1).

The manufacturing method includes a step of bonding a long side of a pair of long films to form a cylindrical long cell, a liquid crystal layer having a constant thickness is formed by a pressure roller after injecting liquid crystal into the long cell. A flexible liquid crystal display element comprising a step, a step of sealing a long cell at a predetermined interval in the short side direction to divide the liquid crystal into a plurality of regions isolated from each other, and a step of separating the long cell at the seal portion It is possible to manufacture.
Japanese Patent Laid-Open No. 11-249158 ([0017] to [0020], FIG. 1)

  However, since the liquid crystal display element according to the above proposal uses ITO (indium, tin oxide), which is an inorganic material, as a transparent electrode material, the electrode peels off when the display device is bent with a small curvature. Or there existed the subject that disconnection was easy to produce.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a method of manufacturing a light modulation element having flexibility that can be bent with a small curvature.

  The method for producing a light modulation element of the present invention includes softening of the synthetic resin film with an electrode made of a transparent organic conductive material, a non-conductive transparent protective film, and a transparent alignment film on the surface of the transparent synthetic resin film. A member forming step of forming a front member sequentially laminated in an atmosphere below the temperature and a back member laminated on the surface of the synthetic resin film with an electrode made of an organic conductive material in an atmosphere below the softening temperature of the synthetic resin film; A convex structure forming step of forming a convex structure along the upper side of the synthetic resin film on the inner side of the electrode surface of at least one of the front member and the back member; and the front member and the back member A cell generating step of applying a bonding agent along both sides and a lower side of at least one of the electrode surfaces, and then applying the other and the electrode surfaces facing each other to generate a bag-shaped cell; A liquid crystal injection step of injecting liquid crystal, a spreading step of pushing down the cell to spread the liquid crystal to a uniform thickness in the cell, and a sealing agent applied to the outside of the convex structure of the cell And a sealing step for sealing the cell.

  With this configuration, the light modulation element has flexibility.

  In the method for producing a light modulation element of the present invention, the member forming step includes a back surface material in which a transparent organic conductive material electrode is laminated on the surface of the synthetic resin film, or a reflective organic conductive material on the surface of the synthetic resin film. You may form the back surface member which laminated | stacked the electrode made from material, or the electrode made from organic electroconductive material which added the reflecting material.

  In the method for manufacturing a light modulation element of the present invention, the organic conductive material may be a polythiophene polymer material.

  In the method for manufacturing a light modulation element of the present invention, the protective film may be a fired product of a mixed material of an organic material and an inorganic material.

  In the method for manufacturing a light modulation element of the present invention, the expanding step may be a step of pressing the cell with a columnar object, or pressing the cell between a roller or a slit to expand the liquid crystal.

  The present invention provides a method for manufacturing a light modulation element having an effect that display performance is not deteriorated even when bent with a small curvature by installing a protective film between an electrode and an alignment film and a convex structure in an opening. It can be provided.

  Hereinafter, an embodiment of a method for manufacturing a light modulation element according to the present invention will be described with reference to the drawings.

That is, the manufacturing method of the light modulation element according to the present invention includes the following six steps as shown in the manufacturing flow charts of FIGS.
(A) An atmosphere of a transparent organic conductive material electrode 111, a non-conductive transparent protective film 121, and a transparent alignment film 131 on the surface of the transparent synthetic resin film 101 is below the softening temperature of the synthetic resin film 101. And a transparent organic conductive material electrode 112, a non-conductive transparent protective film 122, and a transparent alignment film 132 on the surface of the transparent synthetic resin film 102. Member forming stage for forming the back member laminated in order in the atmosphere below the softening temperature. The synthetic resin films 101 and 102 are made of polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polysulfone, polyethersulfone, polyarylate, poly Ether imide, acetyl cellulose, polystyrene, polyethylene and It is desirable to use modified products thereof.

  In addition, the thickness of the synthetic resin films 101 and 102 is preferably set to 100 micrometers (μm) or less in order to ensure sufficient flexibility. Furthermore, it is also possible to improve the chemical resistance, heat resistance, and impact resistance of the film by making the synthetic resin films 101 and 102 have a multilayer structure.

  As the organic conductive material that is a raw material of the electrodes 111 and 112, it is preferable to use a polythiophene-based polymer material having high flexibility. The electrodes 111 and 112 may cover the entire surface of the synthetic resin films 101 and 102 or may be patterned for each pixel.

  The protective films 121 and 122 are provided to prevent peeling of the electrodes 111 and 112 when the light modulation element according to the present invention is bent with a small curvature, and to prevent a short circuit of the electrodes 111 and 112. It is desirable to use a mixture of organic and inorganic materials.

  It is desirable to use an ultraviolet curable resin that is cured by ultraviolet irradiation even at room temperature as the organic material, and extremely small-diameter silica particles as the inorganic material.

As the transparent alignment films 131 and 132, it is desirable to use a rubbing or photo-alignment processed polyimide resin, polyvinyl alcohol resin, or obliquely deposited silicon oxide (SiO) or silicon dioxide (SiO ₂ ).

In addition, although the above demonstrated the case where a back surface member had the same structure as a front surface member, the back surface member should just laminate | stack the electrode made from an organic electroconductive material on the surface of a synthetic resin film, and a synthetic resin film Even if a reflective material and a transparent organic conductive material electrode are laminated on the surface, a reflective organic conductive material electrode may be laminated on the surface of the synthetic resin film. Moreover, the synthetic resin film used for the back member may be transparent or non-transparent.
(B) Convex structure forming step of forming a convex structure 14 along the upper side of the synthetic resin film 101 on the inner side of the upper side 101a of the electrode surface of at least one of the front member and the rear member. As a material of the structure 14, it is desirable to use an ultraviolet curable resin that is cured by ultraviolet irradiation even at room temperature. The convex structure 14 is preferably a columnar body having a rectangular cross section, a triangular cross section, or a semicircular cross section.

  The convex structure 14 can also be formed by a photolithography method.

FIG. 3 is a plan view of one synthetic resin film 101, and the convex structure 14 is formed inside the one synthetic resin film 101 along the upper side 101a.
(C) After applying the adhesive 15 along the both sides 101b and 101d and the lower side 101c of the electrode surface of at least one of the synthetic resin film 101 of the front member and the back member, the other and the electrode surface are applied facing each other. Cell Generation Stage for Generating Bag-shaped Cell 10 That is, as shown in FIG. 3, the adhesive 15 is applied along both sides 101b and 101d of the electrode surface of at least one of the front member and the back member, and the lower side 101c. The

  As the adhesive 15, it is desirable to use a thermosetting resin or a photo-curing resin that has been conventionally used as a sealant for liquid crystal display devices. The thermosetting resin is preferably cured at a temperature equal to or lower than the softening temperature of the synthetic resin films 101 and 102, generally 100 degrees Celsius (° C.) or lower.

In addition, when the synthetic resin films 101 and 102 themselves have thermosetting properties or photocuring properties, the synthetic resin films 101 and 102 can be attached without using the adhesive 15.
(D) Liquid crystal injection step for injecting liquid crystal into the cell 10 When injecting liquid crystal, the top side of the cell 10 may be expanded to inject liquid crystal into the bottom of the cell so that the synthetic resin films 101 and 102 do not contact each other. desirable. This is to prevent bubbles from being mixed into the liquid crystal layer when the liquid crystal adheres to the synthetic resin films 101 and 102 and the liquid crystal is expanded in the next stage.

As the liquid crystal injected into the cell 10, it is possible to use a nematic liquid crystal, a smectic liquid crystal including a ferroelectric liquid crystal and an antiferroelectric liquid crystal, a cholesteric liquid crystal, or a discotic liquid crystal.
(E) The expansion stage in which the cell 10 is pressed to expand the liquid crystal into the cell to a uniform thickness. The cell 10 is pressed between the slits even if the cell 10 is sandwiched between rollers and the liquid crystal is expanded. The liquid crystal may be expanded by passing through. Alternatively, the cell 10 may be placed on a flat table, and the columnar object 16 may be moved from the bottom side to the top side of the cell 10.

  The rollers, slits, and pillars 16 are preferably made of a material having flexibility such as rubber so as not to damage the surface of the cell 10.

  In order to keep the thickness of the liquid crystal layer constant when the liquid crystal is spread, it is desirable to use bead-shaped spacers. However, the spacers are spread on the alignment film surfaces of the synthetic resin films 101 and 102 in advance. It is also possible to mix a spacer in the liquid crystal. If a crimp spacer is used as the spacer, it is possible to prevent the liquid crystal layer from changing due to the movement of the spacer.

  As the spacer material mixed in the liquid crystal, photocuring resin, thermosetting resin, or reaction curing resin can be used. Methacrylic resin, acrylic resin, urethane resin, polyvinyl chloride, vinyl acetate, phenol resin, epoxy Resin, cellulose resin, polyethylene, polypropylene, melanin resin, polyester, polyvinyl butyral, polyvinyl carbazole, polyvinyl acetate, polycarbonate, polystyrene, silicon resin, or a polymer thereof can be used.

In addition, in order to keep the thickness of the liquid crystal layer constant when the liquid crystal is expanded, columnar spacers may be formed on the alignment film 131 of at least one synthetic resin film 101 by a photolithography method.
(F) Sealing step of sealing the cell 10 with the sealing agent 17 applied to the outside of the convex structure 14 of the cell 10 The sealing agent 17 has been conventionally used as a sealing agent for liquid crystal display devices. It is desirable to use a thermosetting resin or a photo-curing resin.

  Since the encapsulant 17 is applied to the outside of the convex structure 14, when the encapsulant 17 is cured, the encapsulant flows into the cell 10 and is mixed into the liquid crystal to display the light modulation element. It becomes possible to prevent the characteristics from deteriorating.

  As an example, a prototype light modulation element uses a polyethylene film having a thickness of 40 μm as the synthetic resin films 101 and 102.

  After improving the surface wettability by UV cleaning on the surface of the polyethylene film, a polythiophene polymer material (PEDOT / PSS) is applied by spin coating, and the temperature is lower than the softening temperature of polyethylene (about 100 ° C) in a constant temperature bath. The electrodes 111 and 112 were formed by baking at 85 ° C.

  Next, a mixture of silica fine particles and an ultraviolet curable resin was applied on the electrode, and the ultraviolet curable resin was cured at a temperature of 85 ° C. or lower to form the protective films 121 and 122. Further, polyimide alignment films (AL-1254, JSR) 131 and 132 were applied on the protective film and rubbed.

  And the convex structure 14 is formed by making it harden, after apply | coating an ultraviolet curable resin to the part on the synthetic resin film 101 used as the opening part of the cell 10. FIG.

  Next, an ultraviolet curable resin is applied as an adhesive 15 on three sides other than the opening of the cell 10 of the synthetic resin film 101, the synthetic resin film 102 is overlaid, and then irradiated with ultraviolet rays to form a cell.

  After applying an ultraviolet curable resin as a sealant 17 to the outside of the convex structure 14, a nematic liquid crystal mixed with a spacer having a diameter of 6 μm is dropped into the deepest part of the cell, and is pressed with a pressure roller to air in the cell. And the thickness of the liquid crystal was made uniform. Finally, the ultraviolet curable resin which is the sealing agent 17 outside the convex structure 14 was cured to seal the cell.

  It was confirmed that the light modulation element prototyped in the above process has a uniform liquid crystal thickness and a uniform molecular orientation of the liquid crystal. Furthermore, since the convex structure 14 is provided, not only can the thickness of the liquid crystal be kept constant even in the vicinity of the opening of the cell, but also excessive liquid crystal outflow when the liquid crystal is pressed by the pressure roller, In addition, it is possible to prevent the ultraviolet curable resin as the sealant 17 from being mixed into the liquid crystal, thereby preventing display quality from being deteriorated.

  When the light modulation element is sandwiched between polarizing plates and a voltage is applied between the electrodes 111 and 112, the transmittance is reduced to 0.0 with a voltage change of 6 volts as shown in the characteristic diagram of the light modulation element in FIG. It was possible to control from 1.0 to 1.0, and it was confirmed that it had the same performance as the conventional light modulation element.

  In addition, since the protective films 121 and 122 are provided between the electrodes 111 and 112 and the alignment films 131 and 132, the electrodes 111 and 112 can be prevented from being dissolved when the alignment films 131 and 132 are formed. It was also confirmed that peeling of the electrodes 111 and 112 or contact of the electrodes 111 and 112 could be prevented even when the modulation element was bent to a radius of 1 mm or less.

  Note that a reflective light modulation element with low power consumption can be manufactured by adding a reflective plate or an electrically conductive electrode that can also serve as a reflective plate to one of the synthetic resin films. In this case, the synthetic resin film may be transparent or non-transparent.

  In addition, in the light modulation element manufactured according to this example, a color filter, a black matrix, or the like may be provided between the synthetic resin film and the electrode, and all the structures used in the conventional light modulation element should be applied. Can do.

  As described above, according to the method for manufacturing a light modulation element according to the present invention, there is an effect that it is possible to provide a light modulation element having excellent display performance and strength while being lightweight and flexible. It is effective as a display or a screen-type lightweight large display.

Flowchart showing the manufacturing process of the light modulation device according to the present invention (part 1) Flowchart showing the manufacturing process of the light modulation device according to the present invention (part 2) Top view of synthetic resin film Characteristics diagram of light modulation device according to the present invention

Explanation of symbols

10 cell 14 convex structure 15 adhesive 16 columnar 17 sealing agent 101, 102 synthetic resin film 101a upper side 101c lower side 101b, 101d both sides 111, 112 electrode 121, 122 protective film 131, 132 alignment film

Claims (5)

A front member in which an electrode made of a transparent organic conductive material, a non-conductive transparent protective film, and a transparent alignment film are sequentially laminated on the surface of the transparent synthetic resin film in an atmosphere below the softening temperature of the synthetic resin film; Forming a back member in which an electrode made of an organic conductive material is laminated on the surface of the synthetic resin film in an atmosphere below the softening temperature of the synthetic resin film; and
A convex structure forming step of forming a convex structure along the upper side of the synthetic resin film on the inner side of the electrode surface of at least one of the front member and the back member;
Cell generation for generating a bag-shaped cell by applying an adhesive along both sides and a lower side of the electrode surface of at least one of the front member and the back member, and then sticking the other and the electrode surface facing each other. Stages,
A liquid crystal injection step of injecting liquid crystal into the cell;
An expansion step of pressing the cell to expand the liquid crystal to a uniform thickness in the cell;
And a sealing step of sealing the cell with a sealing agent applied to the outside of the convex structure of the cell. In the member forming step, an organic material in which a transparent organic conductive material electrode is laminated on the surface of the synthetic resin film, or a reflective organic conductive material electrode or a reflective material is added on the surface of the synthetic resin film. The method for manufacturing a light modulation element according to claim 1, wherein the back member is formed by laminating electrodes made of a conductive material. The method for manufacturing a light modulation element according to claim 1, wherein the organic conductive material is a polythiophene-based polymer material. The method for manufacturing a light modulation element according to any one of claims 1 to 3, wherein the protective film is a fired product of a mixed material of an organic material and an inorganic material. 5. The light according to claim 1, wherein the expanding step is a step of pressing the cell with a columnar object, or sandwiching the cell between a roller or a slit to expand the liquid crystal. A method for manufacturing a modulation element.

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