JP6565505B2 - Method for producing liquid crystal cell and method for producing light control film - Google Patents

Description

  The present invention relates to a light control film that can be used for, for example, an electronic blind that is attached to a window to control the transmission of extraneous light.

  Conventionally, for example, various devices relating to a light control film that is attached to a window to control the transmission of external light have been proposed (Patent Documents 1 and 2). One such light control film uses liquid crystal. The light control film using the liquid crystal is produced by sandwiching a liquid crystal material with a transparent film material on which a transparent electrode is produced, and producing the liquid crystal cell with a linear polarizing plate. As a result, in this light control film, the orientation of the liquid crystal is changed by changing the electric field applied to the liquid crystal, thereby blocking or transmitting the extraneous light, and further changing the amount of transmitted light. To control.

  Conventionally, in a liquid crystal display device, a desired image is displayed by controlling the amount of transmitted light by changing the orientation of the liquid crystal by changing the applied voltage in units of pixels. With regard to such a liquid crystal display device, Patent Document 3 discloses that a liquid crystal injection port is provided on the end surface of the liquid crystal display panel, and the liquid crystal injection port is immersed in a liquid surface of a liquid crystal material in an exhausted environment. A method of manufacturing a liquid crystal cell by injecting a liquid crystal material using a capillary phenomenon is disclosed.

  By the way, if bubbles remain in the liquid crystal layer made of a liquid crystal material in the light control film, the control of transmitted light is locally impaired by the bubbles. Therefore, it is desirable that no bubbles remain in the liquid crystal layer. Thus, it is conceivable to inject the liquid crystal material by applying the method disclosed in Patent Document 3. However, in the case of injecting the liquid crystal material by immersing the liquid crystal injection port provided on the end face in the liquid surface of the liquid crystal material in this way, there is a problem that the productivity is remarkably low due to the time required for the injection of the liquid crystal material. . In addition, it has been found that bubbles cannot be completely prevented in this light control film even by this method.

JP 03-47392 A Japanese Patent Laid-Open No. 08-184273 JP-A-5-11259

  The present invention has been made in view of such a situation, and it is possible to produce a liquid crystal layer by injecting a liquid crystal material in a short time with respect to a light control film or the like so that no bubbles remain in the liquid crystal layer. For the purpose.

  The present inventor has intensively researched to solve the above-mentioned problems, and made a through hole in one of the laminates related to the liquid crystal cell, communicated with the gap related to the liquid crystal layer, and placed the through hole in a flat state. The idea of injecting the liquid crystal material into the gaps in the liquid crystal layer through the present invention has been completed, and the present invention has been completed.

  Specifically, the present invention provides the following.

(1) a first laminated body production step of producing a first laminated body by producing a transparent electrode and an alignment layer on a substrate made of a transparent film material;
A second laminate production step of producing a second laminate by producing at least an orientation layer on a substrate made of a transparent film material;
Laminating and integrating the first and second laminates to produce a laminate relating to a liquid crystal cell in which a portion into which a liquid crystal material is injected is a void; and
A liquid crystal injection step of injecting a liquid crystal material into the gap,
Further, a through-hole forming step is provided in which a through-hole is formed in the first or second laminate, and an injection port for the liquid crystal material communicating with the gap is formed.
The liquid crystal injection step includes
With the orientation where the injection port is on the upper side, in a state where the laminate according to the liquid crystal cell is held flat,
A method of manufacturing a liquid crystal cell, wherein the liquid crystal material is dropped into the injection port in an exhausted environment, and then pressurized with an atmospheric pressure or higher to inject the liquid crystal material into the gap.

  According to (1), by injecting the liquid crystal material in a flat state, the liquid crystal material can be sufficiently injected in a short time so that no bubbles remain in the liquid crystal layer with respect to the light control film or the like. Thus, the liquid crystal layer can be manufactured by injecting the liquid crystal material in a short time.

(2) A liquid crystal cell manufacturing process for manufacturing a liquid crystal cell by the method for manufacturing a liquid crystal cell according to (1),
The manufacturing method of a light control film provided with the manufacturing process of the light control film which clamps the said liquid crystal cell with a linearly-polarizing plate, and produces a light control film.

  According to (2), with respect to the light control film, it is possible to produce a liquid crystal layer by injecting a liquid crystal material in a short time so that no bubbles remain in the liquid crystal layer.

  According to the present invention, it is possible to produce a liquid crystal layer by injecting a liquid crystal material in a short time so that no bubbles remain in the liquid crystal layer in the light control film or the like.

It is a figure which shows the light control film which concerns on 1st Embodiment of this invention. It is a flowchart which shows the manufacturing process of the light control film of FIG. It is a figure where it uses for description of the laminated body in the manufacturing process of FIG. It is a figure which shows the other example of the laminated body of FIG. It is a figure which shows the other example different from the example of FIG. 4 of the laminated body of FIG. It is a figure which shows the other example different from the example of FIG.4 and FIG.5 of the laminated body of FIG. It is a figure where it uses for description of the trimming process in the manufacturing process of FIG.

[First Embodiment]
[Light control film]
FIG. 1 is a cross-sectional view showing a light control film according to the first embodiment of the present invention. This light control film 1 is used by being attached to an area for light control such as a window glass of a building, a showcase, an indoor transparent partition, etc. with an adhesive layer or the like, and the amount of transmitted light can be reduced by changing the applied voltage. Control.

  This light control film 1 is a film material that controls transmitted light using liquid crystal, and is configured by sandwiching a liquid crystal cell 4 for light control film between linear polarizing plates 2 and 3. Here, the linear polarizing plates 2 and 3 are formed by impregnating polyvinyl alcohol (PVA) with iodine or the like, and then stretched to form an optical functional layer that performs an optical function as a linear polarizing plate. TAC (triacetyl cellulose) The optical functional layer is sandwiched between base materials made of a transparent film material such as the above. The linearly polarizing plates 2 and 3 are arranged in the liquid crystal cell 4 by an adhesive layer made of an ultraviolet curable resin or the like in a crossed Nicol arrangement. The linearly polarizing plates 2 and 3 may each be provided with a retardation film for optical compensation on the liquid crystal cell 4 side.

  The liquid crystal cell 4 controls the polarization plane of transmitted light by an applied voltage to a transparent electrode described later. Thereby, the light control film 1 is comprised so that transmitted light can be controlled and various light control can be aimed at.

[Liquid crystal cell]
The liquid crystal cell 4 is configured by sandwiching a liquid crystal layer 8 between an upper laminated body 5U and a lower laminated body 5D which are first and second laminated bodies having a film shape. The lower laminate 5D is formed by producing a transparent electrode 11 and an alignment layer 13 on a base material 6 made of a transparent film material. The upper laminate 5U is formed by laminating a transparent electrode 16 and an alignment layer 17 on a base material 15 made of a transparent film material. The liquid crystal cell 4 controls the orientation of the liquid crystal material provided in the liquid crystal layer 8 by the TN (Twisted Nematic) method by driving the transparent electrodes 11 and 16 provided in the upper laminate 5U and the lower laminate 5D. This controls the plane of polarization of the transmitted light.

  In place of the TN method, a driving method such as a VA (Virtual Alignment) method or an IPS (In-Place-Switching) method may be applied. When driving by the IPS method, either the transparent electrode 11 or 16 of the upper stacked body 5U or the lower stacked body 5D is omitted, and an electric field for driving is applied by patterning the other transparent electrode.

  Although various transparent film materials applicable to this kind of film material can be applied to the base materials 6 and 15, it is desirable to apply a film material having a small optical anisotropy. In this embodiment, although the polycarbonate film provided with the hard-coat layers 6A and 15A is applied to the base materials 6 and 15, a COP (cycloolefin polymer) film, a TAC film, etc. may be applied.

  Various electrode materials applied to this kind of film material can be applied to the transparent electrodes 11 and 16, and in this embodiment, the transparent electrodes 11 and 16 are formed of a transparent electrode material made of ITO (Indium Tin Oxide).

  The alignment layers 13 and 17 are produced by rubbing a polyimide resin layer. The alignment layers 13 and 17 can be applied with various configurations capable of expressing the alignment regulating force with respect to the liquid crystal material related to the liquid crystal layer 8, and may be formed by a so-called photo-alignment layer. You may form and form the fine line-shaped uneven | corrugated shape by a process by a shaping process.

  In addition, although various materials to which the photo-alignment technique can be applied can be applied as the photo-alignment material, in this embodiment, the alignment is not changed by ultraviolet irradiation after the alignment, for example, a light dimerization type. Use materials. The light dimerization type material is described in “M. Schadt, K. Schmitt, V. Kozinkov and V. Chigrinov: Jpn. J. Appl. Phys., 31, 2155 (1992)”, “M. Schadt, H. Seiberle and A. Schuster: Nature, 381, 212 (1996).

  Various liquid crystal materials applicable to this type of light control film can be widely applied to the liquid crystal layer 8. In the liquid crystal cell 4, a sealing agent 19 is arranged in a frame shape so as to surround the liquid crystal layer 8, and the upper stacked body 5U and the lower stacked body 5D are integrally held by the sealing agent 19, and leakage of the liquid crystal material is prevented. . In the light control film 1, bead-shaped spacers 12 are randomly arranged in the liquid crystal layer 8, and the thickness of the liquid crystal layer 8 is defined by the spacers 12. The spacer 12 may be a columnar spacer instead of the bead-shaped spacer 12. In addition, such a columnar spacer can be produced by applying a photoresist on the substrate 6 on which the transparent electrode 11 is produced, and exposing and developing the photoresist.

〔Manufacturing process〕
FIG. 2 is a flowchart showing the manufacturing process of the light control film 1. In the manufacturing process, in the electrode manufacturing process SP2, the transparent electrodes 11 and 16 are respectively formed on the base materials 6 and 15 related to the lower stacked body 5D and the upper stacked body 5U by sputtering using a sputtering apparatus. In the case of the IPS method, the creation of one of the transparent electrodes 11 and 16 is omitted, and a patterning process for patterning the other transparent electrode 11 or 16 is provided.

  Subsequently, in the subsequent alignment layer manufacturing step SP3, the manufacturing process is performed by applying the coating liquids related to the alignment layers 13 and 17 to the base materials 6 and 15 formed the transparent electrodes 11 and 16 in this way, respectively. After drying, the film is heated and cured, whereby the material layers of the alignment layers 13 and 17 are produced. In addition, the alignment layers 13 and 17 are produced by rubbing the base materials 6 and 15 related to the upper laminated body 5U and the lower laminated body 5D formed by preparing the material layers of the alignment layers 13 and 17 in this way. In addition, when applying a photo-alignment layer to the alignment layers 13 and 17, it replaces with the process which concerns on such a rubbing process, and the process of the coating liquid which concerns on a photo-alignment layer, and an exposure process are performed.

  In this manufacturing process, in the subsequent stacking integration process SP4, the sealant 19 is applied to the upper stacked body 5U or the lower stacked body 5D in a frame shape surrounding the liquid crystal layer 8, and then the spacers 12 are arranged. Subsequently, the upper laminated body 5U and the lower laminated body 5D are held and laminated so as to face each other, then pressed, and then the sealing agent 19 is cured to integrate the upper laminated body 5U and the lower laminated body 5D. . The curing process is performed by, for example, semi-curing the sealing agent 19 by irradiation with ultraviolet rays, and then heating and thermally curing.

  Subsequently, in the manufacturing process, in the liquid crystal injection process SP5, a liquid crystal material is injected between the stacked and integrated upper stacked body 5U and lower stacked body 5D to produce the liquid crystal layer 8. Further, in the subsequent trimming step SP6, after cutting off the portion subjected to the injection of the liquid crystal material, in the subsequent sealing step SP7, the portion where the liquid crystal material is exposed by the trimming step is cut off with a sealing agent such as an ultraviolet curable resin. Seal, thereby preventing leakage of the liquid crystal material. In this manufacturing process, the liquid crystal cell 4 is prepared as described above, and in the bonding process SP8, the linear polarizing plates 2 and 3 are bonded to the liquid crystal cell 4 with an adhesive such as an ultraviolet curable resin, and the light control film 1 is used. Is made.

  Accordingly, in this manufacturing process, the first laminate manufacturing process in which the transparent electrode material and the alignment layer are manufactured on the base material made of the transparent film material by the electrode manufacturing process SP2 and the alignment layer manufacturing process SP3 to manufacture the first stacked body. And the 2nd laminated body preparation process which produces at least an orientation layer in the base material by a transparent film material, and produces a 2nd laminated body is comprised.

[Liquid crystal injection process]
FIG. 3 is a plan view showing a configuration of a laminated body (a laminated body related to the liquid crystal cell 4) 5A including the upper laminated body 5U and the lower laminated body 5D which are laminated and integrated in the laminated integration process. In this embodiment, in the lamination integration step SP4, after the sealant 19 is applied in a frame shape surrounding the portion for producing the liquid crystal layer 8, the spacer 12 is arranged to dispose the upper laminate 5U and the lower laminate 5D. By stacking and integrating, a gap 8B having a thickness of the spacer 12 is formed in the stacked body 5A. In the light control film 1, a liquid crystal layer 8 is produced by injecting a liquid crystal material into the gap 8B.

  In this embodiment, the liquid crystal layer 8 is formed in a rectangular shape, and the air gap 8B is formed so that the substantially central portion of one long side according to the rectangular shape extends locally outward. Thus, in the lamination and integration step, the sealing agent 19 is applied in a shape corresponding to the outer shape of the gap 8B.

  In the laminated body 13A, a through hole 19A communicating with the gap 8B is formed in one of the upper laminated body 5U and the lower laminated body 5D in the portion of the gap 8B that extends locally outward in this way. Here, the through hole 19A is a liquid crystal material injection port (which will be referred to as an injection port as appropriate hereinafter). In this embodiment, the liquid crystal material is injected into the gap 8B through the through hole 19A. Thus, the liquid crystal layer 8 is produced.

  Here, the through-hole 19A is formed so as to communicate with the gap 8B, so that after the alignment layer is manufactured in the alignment layer manufacturing process, the laser irradiation is performed until the stacking is performed in the stacking integration process. It is produced by punching or the like.

  Although it seems that it is desirable to make the injection port 19A with a large diameter from the viewpoint of injecting the liquid crystal material in a short time, the liquid crystal material applied to the liquid crystal layer 8 has a high viscosity and the thickness of the gap 8B. Due to the thinness (about 2 to 10 μm), the effect of shortening the injection time is small even if the diameter is increased excessively. On the contrary, the handling property of the laminate 5D or 5U in the manufacturing process is impaired, and the strength of the laminate 5A is impaired. There is a fear. Thereby, the injection port 19A is produced by a circular shape having a diameter of 1 mm or more and 10 mm or less, and more preferably by a circular shape having a diameter of 3 mm or more and 6 mm or less.

  A plurality of injection ports 19A may be provided as shown in FIGS. Further, as shown in FIG. 4, the plurality of inlets 19 </ b> A may be provided on one side of the rectangular shape related to the gap 8 </ b> B, or provided on two opposite sides as shown in FIG. 5. Alternatively, as shown in FIG. 6, it may be provided on four sides of a rectangular shape related to the gap 8B.

  In the liquid crystal injection step SP5, the stacked body 5A is arranged in the chamber in a flat orientation with the injection port 19A facing upward. Here, the flat placement is an arrangement in which the in-plane direction of the stacked body 5A is held in the horizontal direction. In the liquid crystal injection step SP5, the air in the chamber is exhausted while the stacked body 5A is held. When the chamber is sufficiently evacuated, a liquid crystal material is dropped into the inlet 19A, and then air is introduced into the chamber to return to normal pressure (atmospheric pressure). As a result, the liquid crystal material dropped into the injection port 19A enters the air gap 8B through the injection port 19A due to atmospheric pressure and pressure due to capillary action.

  In the liquid crystal injection step SP5, when the liquid crystal material enters the gap 8B through the injection port 19A and the liquid crystal material dropped into the injection port 19A decreases, the liquid crystal material is added dropwise to the injection port 19A. Note that this additional dropping of the liquid crystal material is performed, for example, by monitoring the liquid crystal material dropped into each injection port 19A with an imaging device. A bank is made of, for example, an ultraviolet curable resin, a photoresist material or the like so as to surround the injection port 19A, and a primary holding portion of a liquid crystal material that holds the liquid crystal material in the injection port 19A is configured by the bank, The repeated addition of the liquid crystal material to the inlet 19A may be simplified and further omitted.

  In this embodiment, by injecting the liquid crystal material in a flat manner as described above, the liquid crystal material can be injected in a short time so that no bubbles remain in the liquid crystal layer, and the liquid crystal layer can be manufactured.

  That is, the liquid crystal material is held in the container, and the laminate 5A described above with reference to FIG. 3 is held perpendicular to the liquid surface of the liquid crystal material in the direction in which the injection port 19A is on the lower side. In this state, after evacuating the chamber holding the laminated body, the laminated body is lowered and the inlet 19A is immersed in the liquid crystal material, and then the inside of the chamber is returned to atmospheric pressure, thereby injecting the liquid crystal material. Tried. In this test, the gap 8B for injecting the liquid crystal material was formed in a rectangular shape having a side of 100 mm. The void 8B had a thickness of 4 μm. In this test, it took about 11 hours to inject the liquid crystal material into the gap 8B. In this case, in all of the five tested, bubbles remained at the end opposite to the inlet 19A.

  In contrast, when a liquid crystal material was injected into this test material by the injection method of this embodiment, the injection of the liquid crystal material was completed in 6 hours. In two of the five samples tested, it was confirmed that bubbles remained at the end opposite to the injection port 19A, thereby reducing bubbles remaining. Incidentally, such residual bubbles can be completely prevented by providing a plurality of injection ports 19A.

  FIG. 7 is a diagram for explaining the processing in the trimming step SP6. In this embodiment, as indicated by the cut line 20, the portion provided with the injection port 19 </ b> A is cut out in the trimming step, and then sealed to the end face of the stacked body 5 </ b> A where the liquid crystal material is exposed by the cut out. The agent is applied and cured, thereby preventing leakage of the liquid crystal material.

[Other Embodiments]
The specific configuration suitable for implementing the present invention has been described in detail above. However, the present invention can be combined with the above-described embodiments without departing from the spirit of the present invention, and various modifications can be made. Can do.

  That is, in the above-described embodiment, the case where the liquid crystal material is dropped at the inlet and then the inside of the chamber is returned to the atmospheric pressure has been described. However, the present invention is not limited thereto, and the pressure of the liquid crystal material is further increased by applying a pressure higher than the atmospheric pressure. Injection may be facilitated.

  In the above-described embodiment, the case where the portion where the injection port is manufactured by the trimming process is cut and then sealed with the sealant has been described. However, the present invention is not limited to this, and the size of the portion where the injection port is manufactured is described. When the thickness can be ignored practically, cutting of this portion may be stopped and, for example, an ultraviolet curable resin may be dropped and sealed at the injection port.

DESCRIPTION OF SYMBOLS 1 Light control film 2, 3 Linearly polarizing plate 4 Liquid crystal cell 5D Lower laminated body 5U Upper laminated body 5A Laminated body 6,15 Base material 6A, 15A Hard-coat layer 8 Liquid crystal layer 8B Space | gap 11,16 Transparent electrode 12 Spacer 13, 17 Orientation layer 19 Sealing agent 19A Inlet

Claims (4)

A first laminate production step of producing a first laminate by producing a transparent electrode and an orientation layer on a substrate made of a transparent film material;
A second laminate production step of producing a second laminate by producing at least an orientation layer on a substrate made of a transparent film material;
Laminating and integrating the first and second laminates to produce a laminate relating to a liquid crystal cell in which a portion into which a liquid crystal material is injected is a void; and
A liquid crystal injection step of injecting a liquid crystal material into the gap,
Furthermore, a through hole creating step of creating a through hole in the first or second laminated body and creating an inlet for the liquid crystal material communicating with the gap ;
After the liquid crystal injecting step, a trimming step of cutting out the portion provided with the through hole,
A sealing step in which a sealing agent is applied to a portion that is cut out by the trimming step and the liquid crystal material is exposed ;
The liquid crystal injection step includes
With the orientation where the injection port is on the upper side, in a state where the laminate according to the liquid crystal cell is held flat,
A method of manufacturing a liquid crystal cell, wherein the liquid crystal material is dropped into the injection port in an exhausted environment, and then pressurized with an atmospheric pressure or higher to inject the liquid crystal material into the gap. The through-hole creating step creates a plurality of the through-holes
The manufacturing method of the liquid crystal cell of Claim 1. The plurality of through holes are provided on two opposing sides of the gap.
The manufacturing method of the liquid crystal cell of Claim 2. A process for producing a liquid crystal cell for producing a liquid crystal cell by the method for producing a liquid crystal cell according to any one of claims 1 to 3 ,
A light control film manufacturing method comprising: a light control film manufacturing step of manufacturing a light control film by sandwiching the liquid crystal cell with a linear polarizing plate.

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