JP2020030287A - Dimmer unit, dimming member, and dimmer unit manufacturing method - Google Patents

Abstract

To suppress the occurrence of a bead spacer movable relative to an orientation film.SOLUTION: A dimmer unit 20 comprises a first laminate 30, a second laminate 40, a liquid crystal layer 25 arranged between the first laminate 30 and the second laminate 40, and a plurality of bead spacers 50 arranged between the first laminate 30 and the second laminate 40. The first laminate 30 has a first resin substrate 31 and a first orientation film 33 laminated on the first resin substrate 31. The second laminate 40 has a second resin substrate 41 and a second orientation film 43 laminated on the second resin substrate 41. The first orientation film 33 and the second orientation film 43 are arranged so as to face each other. The liquid crystal layer 25 includes liquid crystal molecules the orientation of which is controlled by voltage application to an electrode provided on at least one of the first laminate 30 and the second laminate 40. The first orientation film 33 includes a plurality of protrusions 35 projecting to the liquid crystal layer 25 side. Only some of the protrusions 35 enclose the bead spacers 50 at least partly and hold the bead spacers.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a light control unit and a light control member having the light control unit. The present invention also relates to a method for manufacturing a light control unit.

  2. Description of the Related Art Conventionally, there has been known a dimming member capable of controlling light transmittance, as described in Patent Documents 1 and 2, for example. As a method of adjusting the light transmittance of the light control member, a method using a liquid crystal as disclosed in Patent Documents 1 and 2 is known. A dimming member using a liquid crystal can be simply configured, and can ensure extremely high light-shielding performance.

  In such a light control member, the liquid crystal is disposed between the two alignment films. Each alignment film is laminated on a transparent substrate. The liquid crystal can maintain a desired thickness of the liquid crystal layer by disposing a spacer having a predetermined size between the transparent base materials. As the spacer, a spherical bead spacer is often used from the viewpoint of handleability.

Japanese Patent No. 6213653 JP 2018-17775 A

  From the viewpoint of assembling efficiency, it has been studied to fix a bead spacer to an alignment film in advance before assembling a pair of base materials. By the way, such a bead spacer may be aggregated before the alignment film is dried after being dispersed in the alignment film. That is, a plurality of bead spacers may be in a solidified state. The aggregated bead spacer easily falls off the alignment film. The bead spacer dropped from the alignment film remains in the liquid crystal layer and can move in the liquid crystal layer with respect to the alignment film. When the aggregated bead spacer moves, air bubbles may be generated in the light control member, or streak-like scratches may be generated in the light control member. Bubbles and streak-like scratches generated on the light control member may deteriorate visibility through the light control member.

  The present invention has been made in consideration of the above points, and has as its object to suppress generation of bead spacers that can move with respect to an alignment film.

The light control unit of the present invention includes:
A first laminate having a first resin base material and a first alignment film laminated on the first resin base material;
It has a second resin base material and a second alignment film laminated on the second resin base material, and is arranged such that the first alignment film and the second alignment film face each other. , A second laminate,
Liquid crystal molecules arranged between the first laminate and the second laminate, the orientation of which is controlled by applying a voltage to an electrode provided on at least one of the first laminate and the second laminate. A liquid crystal layer containing
A plurality of bead spacers disposed between the first laminate and the second laminate,
The first alignment film includes a plurality of first protrusions protruding toward the liquid crystal layer,
Only a portion of the first protrusion at least partially surrounds and holds the bead spacer.

  In the light control unit of the present invention, the first convex portion includes a first holding convex portion that at least partially surrounds the bead spacer and holds the bead spacer, and a first non-holding convex portion that is separated from the bead spacer. And may be included.

  In the light control unit of the present invention, the first non-holding projection may linearly extend at least a part of a circumferential pattern.

  In the light control unit of the present invention, the area of the region surrounded by the peripheral pattern may be 1.1 times or more the area of the bead spacer in plan view.

  In the light control unit of the present invention, a projection height of the first convex portion holding the bead spacer may be not less than 0.2 μm and less than 0.5 μm.

  In the light control unit of the present invention, a projection height of the first protrusion other than the first protrusion holding the bead spacer may be 0.05 μm or more and 0.06 μm or less.

  In the light control unit of the present invention, the thickness of the first alignment film may be not less than 60 nm and not more than 150 nm.

  In the light control unit of the present invention, a ratio of a protrusion height [μm] of the first convex portion holding the bead spacer to a diameter [μm] of the bead spacer is 2.2% or more and less than 5.5. There may be.

The light control member of the present invention,
A pair of substrates,
And any of the above-described light control units disposed between the pair of substrates.

The method for manufacturing the light control unit of the present invention
Producing a first plate having a first resin substrate and a first alignment film laminated on the first resin substrate;
Supplying a liquid crystal material on the first plate;
Laminating the second plate material on the first plate material,
The step of manufacturing the first plate member includes a step of fixing a bead spacer to the first alignment film, and a step of dropping and removing a part of the bead spacer.

  In the step of dropping and removing a part of the bead spacer, the bead spacer having low adhesion strength to the first alignment film may be removed.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the bead spacer movable with respect to an alignment film can be suppressed.

FIG. 1 is a perspective view schematically showing an automobile as an example of a moving body provided with a dimming member. FIG. 2 is a plan view showing the dimming member from the normal direction of the plate surface. FIG. 3 is a cross-sectional view of the light control member along the line III-III in FIG. FIG. 4 is an enlarged plan view showing a part of the light control member. FIG. 5 is a diagram illustrating an example of a method for manufacturing a light control member. FIG. 6 is a diagram for explaining an example of a method for manufacturing the light control member. FIG. 7 is a diagram for explaining an example of a method for manufacturing the light control member. FIG. 8 is a diagram for explaining an example of a method for manufacturing the light control member. FIG. 9 is a diagram for explaining an example of a method for manufacturing the light control member. FIG. 10 is a diagram illustrating an example of a method for manufacturing a light control member. FIG. 11 is a view corresponding to FIG. 3 and is a cross-sectional view of a conventional light control member.

  Hereinafter, an embodiment will be described with reference to the drawings. In the drawings attached to the present specification, the scale and the size ratio in the vertical and horizontal directions are appropriately changed and exaggerated for the sake of convenience of illustration and understanding.

  Note that in this specification, the terms “layer”, “sheet”, and “film” are not distinguished from each other based only on the difference in names. For example, the term “layer” is a concept including a member that can be called a sheet or a film.

  In addition, the “plate surface (sheet surface, film surface)” refers to a target plate-like member (sheet-like or film-like) when viewed as a whole and globally. (A member, a film-shaped member).

  Further, as used herein, to specify the shape and geometric conditions and their degree, for example, terms such as "parallel", "orthogonal", "identical" and the like, values of length and angle, etc. Without being constrained by the meaning, it should be interpreted to include a range in which a similar function can be expected.

  FIG. 1 is a diagram schematically illustrating an automobile as an example of a moving object including a light control member. FIG. 2 is a view of the light control member as viewed from the normal direction of the plate surface. FIG. 3 is a diagram illustrating a cross section of the light control member along the line III-III in FIG. 2. FIG. 4 is an enlarged plan view showing a part of the light control member.

  As shown in FIG. 1, an automobile 1 as an example of a moving object has window glasses such as a sunroof, a rear window, and a side window. Here, an example in which the sunroof 5 is configured by the light control member 10 is illustrated. The vehicle 1 has a power source such as a battery (not shown). The light control member 10 can change the visible light transmittance by applying a voltage. For example, the light control member 10 can change the visible light transmittance between 70% and 1%. By appropriately adjusting the visible light transmittance of the light control member 10, external light such as sunlight can be transmitted with an appropriate amount of light. Further, the light control member 10 can shield external light.

  Here, the visible light transmittance is measured for each wavelength when measured using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation, conforming to JIS K 0115) within a measurement wavelength range of 380 nm to 780 nm. Is specified as the average value of the transmittance at

  FIG. 2 shows the light control member 10 from the normal direction of the plate surface. FIG. 3 is a cross-sectional view of the light control member 10 of FIG. 2 corresponding to line III-III. In the example illustrated in FIGS. 2 and 3, the light control member 10 is disposed between the first substrate 11 and the second substrate 12, which are a pair of substrates, and between the first substrate 11 and the second substrate 12. It has a light control unit 20, a first bonding layer 13 for bonding the first substrate 11 and the light control unit 20, and a second bonding layer 14 for bonding the second substrate 12 and the light control unit 20. I have. The light control member 10 has a wiring 15 for connecting to an external power supply. A voltage can be applied to the light control member 10 from a power supply via the wiring 15. As shown in FIG. 2, the light control member 10 has a flat rectangular shape in plan view, but the light control member 10 may be curved. The light control member 10 can appropriately have a shape and a size according to the applied light control member.

  Hereinafter, each component of the light control member 10 will be described.

  First, the first substrate 11 and the second substrate 12 will be described. When the first substrate 11 and the second substrate 12 are used for the sunroof 5 of the automobile 1 as in the example shown in FIG. 1, the dimming member 10 sufficiently transmits the external light without blocking the external light. It is preferable to use a material having a high visible light transmittance, for example, a material having a visible light transmittance of 90% or more. Examples of the material of the first substrate 11 and the second substrate 12 include inorganic glass such as soda lime glass and blue plate glass, and resin glass such as polycarbonate and acrylic. When inorganic glass is used for the first substrate 11 and the second substrate 12, the light control member 10 having excellent heat resistance and scratch resistance can be obtained. When resin glass is used for the first substrate 11 and the second substrate 12, the light control member 10 can be reduced in weight.

  Further, the first substrate 11 and the second substrate 12 preferably have a thickness of 1 mm or more and 5 mm or less. With such a thickness, the first substrate 11 and the second substrate 12 having excellent strength and optical characteristics can be obtained. The first substrate 11 and the second substrate 12 may be made of the same material and may be the same, or may be different from each other in at least one of the material and the configuration.

  Next, the first bonding layer 13 and the second bonding layer 14 will be described. The first bonding layer 13 is disposed between the first substrate 11 and the light control unit 20, and bonds the first substrate 11 and the light control unit 20 to each other. The second bonding layer 14 is disposed between the second substrate 12 and the light control unit 20, and bonds the second substrate 12 and the light control unit 20 to each other.

  As such a first bonding layer 13 and a second bonding layer 14, layers made of various adhesive or tacky materials can be used. It is preferable that the first bonding layer 13 and the second bonding layer 14 have high visible light transmittance. As a typical bonding layer, a layer made of polyvinyl butyral (PVB) can be exemplified. Alternatively, the bonding layer may be a layer made of EVA (ethylene / vinyl acetate copolymer), COP (cycloolefin polymer), or the like. The thickness of each of the first bonding layer 13 and the second bonding layer 14 is preferably 0.15 mm or more and 1 mm or less. The first bonding layer 13 and the second bonding layer 14 may be made of the same material and have the same configuration, or may be different from each other in at least one of the material and the configuration.

  The light control member 10 is not limited to the illustrated example, and may be provided with another functional layer expected to exhibit a specific function. In addition, one functional layer may perform two or more functions. For example, the first substrate 11 and the second substrate 12, the first bonding layer 13, and the second bonding layer 14 of the light control member 10 may be used. Some function may be given to at least one of the first laminated body 30 and the second laminated body 40 of the light control unit 20 described later. Examples of the functions that can be provided to the light control member 10 include an anti-reflection (AR) function, a hard coat (HC) function having scratch resistance, an infrared shielding (reflection) function, an ultraviolet shielding (reflection) function, and an anti-reflection function. A dirty function can be exemplified.

  Next, the light control unit 20 will be described. The light control unit 20 is formed in a flexible film shape. The light control unit 20 can change the visible light transmittance by applying a voltage. That is, the light control unit 20 provides the light control member 10 with a light control function. The light modulating unit 20 includes a first laminate 30 and a second laminate 40, a liquid crystal layer 25 disposed between the first laminate 30 and the second laminate 40, and a first laminate 30 and a second laminate. And a bead spacer 50 disposed between the bodies 40. Further, the dimming unit 20 has a sealing material 27 surrounding the liquid crystal layer 25 between the first stacked body 30 and the second stacked body 40.

  The first stacked body 30 is disposed between the first resin base 31, the first alignment film 33 stacked on the first resin base 31, and the first resin base 31 and the first alignment film 33. And a first electrode 37. Similarly, the second laminate 40 includes a second resin base 41, a second alignment film 43 stacked on the second resin base 41, and a second alignment base 43 between the second resin base 41 and the second alignment base 43. And a second electrode 47 arranged. The first stacked body 30 and the second stacked body 40 are arranged such that the first alignment film 33 and the second alignment film 43 of the second stacked body 40 face each other.

  The first resin base material 31 is a member for appropriately supporting the first alignment film 33 and the first electrode 37. Similarly, the second resin base 41 is a member for appropriately supporting the second alignment film 43 and the second electrode 47. As the material of the first resin base material 31 and the second resin base material 41, it is preferable to use a material having flexibility and high visible light transmittance. Examples of the first resin base material 31 and the second resin base material 41 include acetylcellulose resins such as triacetylcellulose (TAC), polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), Polyolefin resins such as polyethylene (PE), polypropylene (PP), polystyrene, polymethylpentene, and EVA; vinyl resins such as polyvinyl chloride and polyvinylidene chloride; acrylic resins; polyurethane resins; polysulfone (PEF); Examples include resins such as ethersulfone (PES), polycarbonate (PC), polysulfone, polyether (PE), polyetherketone (PEK), (meth) acrylonitrile, cycloolefin polymer (COP), and cycloolefin copolymer. Bets can be, in particular, polycarbonate, cycloolefin polymer, a resin such as polyethylene terephthalate are preferred. The visible light transmittance of the first resin base 31 and the second resin base 41 is preferably 90% or more. Also, in the case of polyethylene terephthalate, for example, the first resin base 31 and the second resin base 41 preferably have a thickness of 30 μm or more and 250 μm or less. With such a thickness, the first resin base 31 and the second resin base 41 excellent in strength and optical characteristics can be obtained. The first resin base 31 and the second resin base 41 may be made of the same material and may be the same, or may be different from each other in at least one of the material and the configuration.

  The first alignment film 33 and the second alignment film 43 are layers adjacent to the liquid crystal layer 25 and regulate the alignment of liquid crystal molecules in the liquid crystal layer 25. The method for manufacturing the first alignment film 33 and the second alignment film 43 is not particularly limited. The first alignment film 33 and the second alignment film 43 having a liquid crystal alignment ability can be manufactured by an arbitrary method. For example, the first alignment film 33 and the second alignment film 43 may be manufactured by performing a rubbing process on a resin layer of polyimide or the like, or a polymer film may be irradiated with linearly polarized ultraviolet light to increase the polarization direction. The first alignment film 33 and the second alignment film 43 may be manufactured based on a photo-alignment method for selectively reacting molecular chains. Instead of the first alignment film 33 and the second alignment film 43 by the rubbing process, a fine line-shaped uneven shape manufactured by the rubbing process is manufactured by a shaping process to form the first alignment film 33 and the second alignment film. 43 may be produced. In the case where a GH method is used for a liquid crystal layer 25 described later, a rubbing process may not be performed.

  The thickness T of the first alignment film 33 is, for example, not less than 60 nm and not more than 150 nm. Similarly, the thickness T of the second alignment film 43 is, for example, not less than 60 nm and not more than 150 nm. Note that the thickness of the first alignment film 33 and the thickness of the second alignment film 43 are different from each other at a number of measurement positions (for example, thirty points) considered to be able to reflect the overall tendency. The average of the thickness and the average of the thickness of the second alignment film 43 can be specified. In particular, the thickness of the first alignment film 33 and the thickness of the second alignment film 43, which are manufactured by a manufacturing method described later and have a specific configuration described here, are specified by an average value of thirty measurement points. can do. The thickness of the first alignment film 33 is measured at a portion excluding a first protrusion 35 described later, specifically, at a point separated from the first protrusion 35 by 6 μm or more. The thicknesses of the first alignment film 33 and the second alignment film 43 can be measured from, for example, images of the cross sections of the first stacked body 30 and the second stacked body 40 taken by a scanning electron microscope (SEM).

  As shown in FIG. 3, the first alignment film 33 includes a plurality of first protrusions 35 protruding toward the liquid crystal layer 25. As shown in FIG. 3, the first holding protrusion 351 that is a part of the first protrusion 35 at least partially surrounds the bead spacer 50 and holds the bead spacer 50. Further, there is a first non-holding convex portion 352 which is another part of the first convex portion 35 which does not hold the bead spacer 50. The first non-holding projection 352 that does not hold the bead spacer 50 is separated from the bead spacer 50. In other words, only a part of the first convex portion 35 at least partially surrounds the bead spacer 50 and holds the bead spacer 50.

  The bead spacer 50 is fixed to the first alignment film 33 by the first holding protrusion 351 of the first protrusion 35 holding the bead spacer 50. As shown in FIG. 4, the first non-holding protrusion 352 of the first protrusion 35 that does not hold the bead spacer 50 linearly extends at least a part of the circumferential pattern in plan view. In the example shown in FIG. 4, the first non-holding convex portion 352 extends along the entire circumferential pattern in plan view.

  The first non-holding convex portions 352 are traces that are left when the bead spacers 50 fall off from the first alignment film 33 in a manufacturing process described later. The bead spacers 50 having a low bonding strength with respect to the first alignment film 33 fall off the first alignment film 33 and are removed. For example, in the bead spacers 50 aggregated in the manufacturing process, the number of the bead spacers 50 held increases with respect to the length of the first protrusion 35 holding the bead spacers 50, so that the adhesion strength to the first alignment film 33 is increased. Weakens. The area surrounded by the peripheral pattern formed by the first non-holding convex portions 352 of the traces of the aggregated bead spacers 50 falling out has the size of the plurality of bead spacers 50 in plan view. That is, as shown in FIG. 4, the area of the region surrounded by the peripheral pattern is at least 1.02 times the area of the bead spacer 50 in plan view.

  The protrusion height Ha of the first protrusion 35 (first holding protrusion 351) holding the bead spacer 50 is not less than 0.2 μm and less than 0.5 μm. The protrusion height of the first protrusion 35 (first non-holding protrusion 352) that does not hold the bead spacer 50, that is, the protrusion height of the first protrusion 35 other than the first protrusion 35 that holds the bead spacer 50. Hb is not less than 0.2 μm and not more than 0.5 μm. Here, the protruding height of the first convex portions 35 can be specified as an average of the protruding heights of the number (for example, thirty) of the first convex portions 35 considered to be able to reflect the overall tendency. The protruding height of each first convex portion 35 is defined by the protruding height (thickness) at the highest point of the first convex portion 35. In particular, the protrusion height of the first convex portion 35 which is manufactured by a manufacturing method described later and has a specific configuration described here can be an average value of measurement values of thirty points. The protrusion heights Ha and Hb of the first convex portion 35 can be measured by, for example, a scanning white interferometer (“Zygo” manufactured by Zygo Corporation).

As the first electrode 37 and the second electrode 47, for example, a tin oxide-based, indium oxide-based, or zinc oxide-based transparent metal thin film can be used. Examples of tin oxide (SnO ₂ ) include nesa (tin oxide SnO ₂ ), ATO (Antimony Tin Oxide: antimony-doped tin oxide), and fluorine-doped tin oxide. Examples of indium oxide (In ₂ O ₃ ) include indium oxide, ITO (Indium Tin Oxide), and IZO (Indium Zinc Oxide). Examples of zinc oxide (ZnO) include zinc oxide, AZO (aluminum-doped zinc oxide), and gallium-doped zinc oxide. In the present embodiment, the first electrode 37 and the second electrode 47 are formed as transparent electrodes by ITO. The arrangement of the first electrode 37 and the second electrode 47 is not particularly limited, and the electrodes may be arranged only at predetermined positions by patterning or may be arranged in a solid pattern. An electric field acting on the liquid crystal layer 25 disposed between the first electrode 37 and the second electrode 47 is formed in accordance with the voltage applied to the first electrode 37 and the second electrode 47, and is included in the liquid crystal layer 25. Of the liquid crystal molecules to be controlled. The visible light transmittance of the first electrode 37 and the second electrode 47 is preferably, for example, 50% or more. The thickness of the first electrode 37 and the second electrode 47 is, for example, not less than 50 μm and not more than 175 μm.

  The liquid crystal layer 25 can use, for example, a VA (Vertical Alignment) method, a TN (Twisted Nematic) method, an IPS (In Plane Switching) method, an FFS (Fringe Field Switching) method, or a GH (Guest Host) method. In the present embodiment, as an example, the liquid crystal layer 25 uses a GH method. When using the GH method, the liquid crystal layer 25 contains liquid crystal molecules and a dichroic dye composition.

  An electric field is formed by applying a voltage to at least one of the electrodes 37 and 47 via the wiring 15, and the orientation of the liquid crystal molecules in the liquid crystal layer 25 can be changed by the action of the electric field. The polarization direction of light passing through the liquid crystal layer 25 can be changed depending on the orientation of the liquid crystal molecules. For example, in the case where a GH type liquid crystal is used, the liquid crystal molecules and the dichroic dye composition are arranged vertically to the first alignment film 33 and the second alignment film 43 when no voltage is applied, and light is transmitted. I do. As the voltage is applied, the liquid crystal molecules and the dichroic dye composition change from vertical to horizontal with respect to the first alignment film 33 and the second alignment film 43, and the visible light transmittance decreases. In a state where the voltage is sufficiently applied, the liquid crystal molecules and the dichroic dye composition are arranged horizontally with respect to the first alignment film 33 and the second alignment film 43 to block light. As described above, the dimming unit 20 can adjust the visible light transmittance by changing the orientation of the liquid crystal molecules of the liquid crystal layer 25 by controlling the application of the voltage.

  The thickness of the liquid crystal layer 25 is, for example, 6 μm or more and 9 μm or less. The thickness of the liquid crystal layer 25 is equal to the size of the space between the first laminate 30 and the second laminate 40 secured by the bead spacer 50. Here, the thickness of the liquid crystal layer 25 can be specified as an average of the thickness of the liquid crystal layer 25 at a number of measurement positions (for example, thirty points) considered to be able to reflect the overall tendency. In particular, the thickness of the liquid crystal layer 25 which is manufactured by a manufacturing method described later and has a specific configuration described here can be an average value of the measured values of thirty points.

  As shown in FIG. 2, the sealing material 27 surrounds the liquid crystal layer 25 in a circumferential shape. That is, the sealing material 27 partitions the liquid crystal layer 25. Further, as shown in FIG. 3, the sealing material 27 is provided between the first stacked body 30 and the second stacked body 40. The sealing material 27 plays a role of preventing liquid crystal molecules constituting the liquid crystal layer 25 from leaking from between the first stacked body 30 and the second stacked body 40, and also functions to prevent the first stacked body 30 and the second stacked body 40. And serves to fix them to each other. The sealing material 27 can be formed from, for example, a thermosetting resin such as an epoxy resin or an acrylic resin, or an ultraviolet-curable resin.

  The bead spacer 50 is disposed between the first stacked body 30 and the second stacked body 40, and secures a space between the first stacked body 30 and the second stacked body 40. The space is filled with a liquid crystal material containing liquid crystal molecules, whereby a liquid crystal layer 25 is formed. The liquid crystal layer 25 described above controls the amount of phase modulation of transmitted light, and therefore has a certain thickness between the first laminate 30 and the second laminate 40. Is required. For this reason, the bead spacer 50 is preferably spherical. The diameter of the bead spacer 50 is, for example, 6 μm or more and 9 μm or less. Here, the diameter of the bead spacers 50 can be specified as the average of the diameters of the number (for example, thirty) of bead spacers that can reflect the overall tendency. In particular, the diameter of the bead spacer 50 described here can be an average value of thirty measured values.

  Further, the ratio of the protrusion height [μm] of the first convex portion 35 holding the bead spacer 50 to the diameter [μm] of the bead spacer 50 is preferably 2.2% or more and less than 5.5%. . As described above, the diameter [μm] of the bead spacer 50 can be specified as an average value of a sufficient number considered to be able to reflect the overall tendency, and the protrusion height of the first convex portion 35 is also reduced. It can be specified as a sufficient number of average values considered to be able to reflect the trend.

  The diameter of the bead spacer 50 can be measured by, for example, a dynamic light scattering method or a laser diffraction method.

The areal density of the bead spacer 50 in a plan view is, for example, 30 [pieces / mm ² ] or more and 160 [pieces / mm ² ] or less. When the bead spacers are uniformly dispersed throughout the light control unit 20, the surface density of the bead spacers is determined by counting the number of bead spacers 50 included in a certain area (for example, 1 mm square) of the light control unit 20. Can be specified. In particular, the surface density of the bead spacers 50 in the light control unit 20 manufactured by a manufacturing method described later can be defined by the number of bead spacers 50 included in a 1 mm square. When the bead spacers 50 are agglomerated, that is, when a plurality of bead spacers 50 are in a lump, the number of the aggregate of the bead spacers 50, that is, the lump of the bead spacers 50 is counted as one bead spacer 50.

  The plurality of bead spacers 50 are discretely arranged between the first laminate 30 and the second laminate 40. The bead spacer 50 is formed of an inorganic material such as silica, an organic material, or a core-shell structure obtained by combining these materials.

  The bead spacer 50 is fixed to the first alignment film 33. That is, in the liquid crystal layer 25, the movement of the bead spacer 50 with respect to the first alignment film 33 is restricted. For this reason, it is possible to prevent the bubbles from being generated in the liquid crystal layer 25 and the generation of streaks due to the movement of the bead spacer 50, and to deteriorate the visibility through the light control member 10. Can be prevented.

  In addition to the bead spacers 50, a columnar spacer or the like may be disposed between the first stacked body 30 and the second stacked body 40. The columnar spacer can be formed at a desired position using a photolithography technique.

  Next, an example of a method for manufacturing the light control member 10 and the light control unit 20 will be described with reference to FIGS.

  First, as shown in FIG. 5, a first plate material 30a in which bead spacers 50 are uniformly dispersed is prepared. The first plate member 30a is a member that forms the first laminate 30 by being trimmed. The first plate 30a in which the bead spacers 50 are uniformly dispersed can be manufactured, for example, as follows. First, a first electrode 37 is formed on the first resin substrate 31 by sputtering or the like. Next, bead spacers 50 are sprayed on the first electrodes 37. Thereafter, a composition that forms the first alignment film 33 is applied on the first resin base material 31. At this time, the first convex portion 35 is formed due to the viscosity of the composition forming the first alignment film 33 or the surface tension between the bead spacer 50 and the composition forming the first alignment film 33. The first foot portion 35 a is formed between the bead spacer 50 and the first resin base material 31. Note that the bead spacers 50 may be dispersed in a composition that forms the first alignment film 33, and a composition containing the bead spacers 50 may be applied on the first resin base material 31. Thereafter, the composition is volatilized in a drying oven and dried. Next, a first alignment film 33 is formed by applying an alignment regulating force to the coating film by rubbing, optical alignment, or the like. Thus, the second plate member 40a on which the bead spacers 50 are scattered is obtained.

  Note that a part of the bead spacer 50 aggregates after being dispersed in the composition forming the first alignment film 33 and before drying. That is, as shown in FIG. 5, a plurality of bead spacers 50 gather.

  When the composition that forms the first alignment film 33 is dried, the first foot portion 35a solidifies to form the first convex portion 35. Part of the first protrusion 35 holds the bead spacer 50. Thereby, the bead spacer 50 is fixed to the first alignment film 33. The protrusion height of the first protrusion 35 is sufficiently high at 0.2 μm or more so that the first protrusion 35 can securely hold the bead spacer 50. The ratio of the projection height [μm] of the first projection 35 holding the bead spacer 50 to the diameter [μm] of the bead spacer 50 is 2.2% or more.

  The viscosity of the composition can be adjusted by adjusting the amount of polyimide or the like contained in the composition that forms the first alignment film 33. Thereby, the height of the first foot portion 35a can be adjusted. That is, the height of the first convex portion 35 formed from the first foot portion 35a can be adjusted.

  Next, as shown in FIG. 6, a part of the bead spacers 50 dispersed on the first alignment film 33 is dropped and removed. The bead spacer 50 to be removed is a bead spacer 50 having a low fixing strength to the first alignment film 33. Specifically, a part of the bead spacer 50 is dropped from the first alignment film 33 and removed by the roller 70 having adhesiveness. Among the bead spacers 50 held by the first convex portions 35, the bead spacers 50 that fall off have weak adhesion strength to the first alignment film 33. However, the method of dropping and removing the bead spacers 50 is not limited to dropping by the roller 70 having an adhesive property, and other methods such as dropping by suction and the like can be used.

  The bead spacer 50 having a weak fixing strength with respect to the first alignment film 33 typically includes an aggregated bead spacer 50. By appropriately setting the adhesiveness of the roller 70, only the bead spacers 50 having low adhesion strength to the first alignment film 33 can be selectively dropped from the first alignment film 33 and removed. In addition, the bead spacers 50 having low bonding strength to the first alignment film 33 can be easily dropped and removed. For example, the aggregated bead spacers 50 can be dropped and removed. The degree of fixation of the bead spacers 50 to the first alignment film 33 is adjusted so that the aggregated bead spacers 50 can be selectively dropped and removed. Specifically, the projection height of the first convex portion 35 (first retaining convex portion 351) holding the bead spacer 50 is sufficiently low at 0.5 μm or less. The ratio of the protrusion height [μm] of the first protrusion 35 (first holding protrusion 351) holding the bead spacer 50 to the diameter [μm] of the bead spacer 50 is less than 5.5%. .

  At the mark where the bead spacer 50 has fallen, a first non-holding protrusion 352 which is the first protrusion 35 that does not hold the bead spacer 50 is left as a drop mark. The first non-holding convex portion 352 is separated from the bead spacer 50. As shown in FIG. 4, the first non-holding convex portion 352 has a shape extending linearly at least a part of the circumferential pattern that holds the bead spacer 50 in a plan view.

  Next, as shown in FIG. 7, a sealing material 27a is applied in a circumferential shape. The sealing material 27a is a viscous liquid material having adhesiveness or tackiness. The sealing material 27a forms the sealing material 27 by being cured. Thereafter, as shown in FIG. 8, a liquid crystal material 25a containing liquid crystal molecules is supplied to a region on the first plate member 30a surrounded by the sealing material 27a.

  Next, as shown in FIG. 9, the second plate member 40a is laminated on the first plate member 30a under reduced pressure. When laminating the second plate member 40a on the first plate member 30a, the second plate member 40a may be pressed with a roller or the like. The second plate 40a is a member that forms the second stacked body 40 by being trimmed, and can be manufactured, for example, in the same process as the first plate 30a. That is, the second plate member 40 a is formed by first forming the second electrode 47 on the second resin base material 41, and then applying the composition to form the second alignment film 43 on the second resin base material 41. And volatilized in a drying furnace, and thereafter, an alignment regulating force is applied to the coating film, whereby the second alignment film 43 is manufactured.

  The liquid crystal material 25a filled in the space secured by the bead spacer 50 between the first plate 30a and the second plate 40a becomes the liquid crystal layer 25. After that, the sealing material 27a is deformed and hardened by ultraviolet irradiation and heat treatment to become the sealing material 27, and the first plate 30a and the second plate 40a are joined. Through the above steps, a stacked body including the first plate 30a, the second plate 40a, and the liquid crystal layer 25 disposed between the first plate 30a and the second plate 40a is prepared.

  Next, a part of the first plate member 30a and the second plate member 40a is cut to remove an extra area of the outer periphery of the first plate member 30a and the second plate member 40a, that is, the first plate member 30a and the second plate member 40a are trimmed. I do. This cutting is preferably performed at least partially on the sealing material 27. The trimming of the first plate 30a and the second plate 40a can be performed by using a tool such as a punching blade or a cutter. Thus, the light control unit 20 is obtained by the first plate member 30a becoming the first laminate 30 and the second plate member 40a becoming the second laminate 40.

  Finally, as shown in FIG. 10, the first bonding layer 13 and the first substrate 11 are stacked on the side of the first laminate 30 of the light control unit 20, and the light control unit 20 and the first substrate 11 are bonded. I do. Similarly, the second bonding layer 14 and the second substrate 12 are stacked on the side of the second laminated body 40 of the light control unit 20, and the light control unit 20 and the second substrate 12 are bonded. Thereby, the light control member 10 shown in FIG. 3 is manufactured.

  By the way, as shown in FIG. 11, the conventional light control member 110 includes a bead spacer 150 aggregated in the light control unit 120. The agglomerated bead spacers 150 can easily fall off because of their weak fixing strength to the first alignment film 133. In particular, when the first plate member and the second plate member are laminated in the above-described process of manufacturing the light control member, pressure is easily applied to the bead spacers 150, so that the aggregated bead spacers 150 can fall off. The dropped bead spacer 150 remains in the liquid crystal layer 125 and can move in the liquid crystal layer 125 with respect to the alignment films 33 and 43. When the aggregated bead spacers 150 move with respect to the alignment films 133 and 143, streak-like scratches may be generated on the alignment films 133 and 143. In addition, the presence of the aggregated bead spacers 150 makes the pressure resistance of the liquid crystal layer 125 non-uniform. In particular, in a high-temperature and high-humidity environment, bubbles in the liquid crystal layer 125 due to deformation of the first laminate 130 and the second laminate 140. Can be generated. When streak-like scratches or bubbles are generated in the light control member 110, visibility through the light control member 110 can be deteriorated.

  On the other hand, in the present embodiment, in the manufacturing process of the light control unit 20, before laminating the first plate member 30a and the second plate member 40a, the bead spacer 50 having a weak bonding strength is dropped and removed by the roller 70. are doing. The aggregated bead spacers 50 are included in the bead spacers 50 having a low fixing strength to be removed. Therefore, when laminating the first plate member 30a and the second plate member 40a, the aggregated bead spacers 50 are removed. For this reason, generation of streak-like scratches and bubbles caused by the aggregated bead spacers can be suppressed.

  As a result of dropping the bead spacers 50 having weak bonding strength such as the agglomerated bead spacers 50 and the like, in the light control unit 20 of the present embodiment, the first protrusion 35 of the first alignment film 33 which is a part of the first protrusion 35 is formed. Only the holding protrusion 351 at least partially surrounds the bead spacer 50 and holds the bead spacer 50. On the other hand, the first non-holding convex portion 352, which is another part of the first convex portion 35 that does not hold the bead spacer 50, is a drop mark where the held bead spacer 50 is dropped, and Separated. The first non-holding convex portion 352 linearly extends at least a part of the circumferential pattern. Since the first non-holding convex portion 352 is a trace of the bead spacer 50 falling off from the first alignment film 33, the presence of the first non-holding convex portion 352 indicates that the bead spacer 50 has dropped. I have. In other words, since only a part of the first convex portion 35 holds the bead spacer 50, generation of streak-like scratches and bubbles caused by the aggregated bead spacer is suppressed.

  The area surrounded by the circumferential pattern of the first non-holding convex portion 352 is 1.02 times or more the area of the bead spacer 50 in plan view. In other words, this indicates that the first non-holding convex portion 352 has surrounded the plurality of bead spacers 50, that is, the aggregated bead spacers. The presence of such first non-retaining projections 352 indicates that the aggregated bead spacers 50 have fallen off, and therefore the generation of streak-like scratches and bubbles caused by the aggregated bead spacers is suppressed. I have.

  Further, in the light control unit 20 of the present embodiment, the projection height of the first convex portion 35 (first retaining convex portion 351) holding the bead spacer 50 is not less than 0.2 μm and less than 0.5 μm, and The protrusion height of the first protrusions 35 (first non-holding protrusions 352) other than the first protrusions 35 holding the spacer 50 is not less than 0.2 μm and less than 0.5 μm. In such a case, the bead spacer 50 having a weak fixing strength can be easily dropped and removed from the first protrusion 35 while the first protrusion 35 reliably holds the bead spacer 50. Therefore, in the manufacturing process of the light control unit 20, the aggregated bead spacers 50 can be easily dropped and removed by the roller 70 or the like. Therefore, generation of streak-like scratches and bubbles due to the aggregated bead spacers 50 can be suppressed.

  Further, the thickness of the first alignment film 33 is not less than 60 nm and not more than 150 nm. In such a case, the bead spacer 50 can be easily dropped from the first alignment film 33. The agglomerated bead spacer 50 can be easily dropped off by the roller 70 or the like. Therefore, generation of streak-like scratches and bubbles due to the aggregated bead spacers 50 can be suppressed.

  Further, the ratio of the protrusion height [μm] of the first convex portion 35 holding the bead spacer 50 to the diameter [μm] of the bead spacer 50 is 2.2% or more and less than 5.5%. In such a case, the bead spacer 50 held by the first convex portion 35 is hard to fall off. In the manufacturing process of the light control unit 20, the aggregated bead spacers 50 can be easily dropped off by the roller 70 or the like. Therefore, generation of streak-like scratches and bubbles due to the aggregated bead spacers 50 can be suppressed.

  As described above, the light modulating unit 20 of the present embodiment includes the first laminate 30 having the first resin base 31 and the first alignment film 33 laminated on the first resin base 31; It has a second resin substrate 41 and a second alignment film 43 laminated on the second resin substrate 41, and is arranged such that the first alignment film 33 and the second alignment film 43 face each other. The second stacked body 40, and the electrodes 37, 47 provided between the first stacked body 30 and the second stacked body 40 and provided on at least one of the first stacked body 30 and the second stacked body 40. A liquid crystal layer 25 including liquid crystal molecules whose orientation is controlled by applying a voltage to the first laminate 30 and a plurality of bead spacers 50 disposed between the first laminate 30 and the second laminate 40. The alignment film 33 includes a plurality of first protrusions 35 protruding toward the liquid crystal layer 25, and only a part of the first protrusions 35 Surrounds Zusupesa 50 at least partially holding the bead spacers 50. In such a light control unit 20, there is a first non-holding convex portion 352 which is another part of the first convex portion 35 that does not hold the bead spacer 50. The presence of the first non-holding convex portions 352 indicates that the bead spacers 50 have fallen off, and in particular, that the aggregated bead spacers 50, which are bead spacers 50 having low adhesion strength to the first alignment film 33, have come off and have been removed. Show. Therefore, since only a part of the first convex portion 35 holds the bead spacer 50, generation of streak-like scratches and bubbles caused by the aggregated bead spacer is suppressed.

  Such a light control member 10 is not limited to the sunroof of the automobile 1 as shown in FIG. 1 and may be used for a rear window and a side window. Moreover, you may use for the transparent part of the window or door of mobile bodies other than a motor vehicle, such as a railroad vehicle, an aircraft, a ship, and a spacecraft.

  Further, the dimming member 10 may be used in addition to a moving body, in particular, a place that separates the room from the outside, such as a transparent part of a window or door of a building or a store, a house, a window or a door of a building, a refrigerator, a display box, or a cabinet. It can also be used for transparent parts of windows or doors of storage or storage facilities.

  In the above-described embodiment, the light control member 10 is formed by disposing the light control unit 20 between the first substrate 11 and the second substrate 12. However, the light control member 10 may be formed by bonding the light control unit 20 to one substrate.

  In the above-described embodiment, the bead spacers 50 are manufactured by being uniformly dispersed in the first alignment film 33. However, the bead spacers 50 may be unevenly dispersed in the first alignment film 33.

  Further, in the above-described embodiment, the light control unit 20 has only the bead spacer 50 fixed to the first alignment film 33. However, the light control unit 20 may further include a second bead spacer fixed to the second alignment film 43. In this case, similarly to the above-described first alignment film 33, the second alignment film 43 includes a plurality of second convex portions protruding toward the liquid crystal layer 25. A part of the second convex portion at least partially surrounds the second bead spacer and holds the second bead spacer. The second bead spacer is fixed to the second alignment film 43 by the second protrusion holding the second bead spacer. Other second projections that do not hold the second bead spacer among the second projections linearly extend at least a part of the circumferential pattern in plan view.

  The protrusion height of the second protrusion holding the second bead spacer is 0.2 μm or more and less than 0.5 μm, and the protrusion height of the second protrusion not holding the second bead spacer is 0.2 μm. It is preferably at least 0.5 μm. Further, it is preferable that the ratio of the protrusion height [μm] of the second convex portion holding the second bead spacer is not less than 2.2% and less than 5.5%. In such a case, in the manufacturing process of the light control unit 20, similarly to the first plate member 30 a that forms the first laminate 30, the adhesive strength of the second bead spacer is reduced by an adhesive roller. By removing the weak ones from the second alignment film 43 and removing them, the aggregated second bead spacers can be easily dropped and removed.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

  As examples and comparative examples, dimming members having dimming units having different protrusion heights of the first protrusions and different thicknesses of the first alignment film 33 were prepared. The manufacturing method of the light control member having the light control unit adopts the above-described manufacturing method, and is common to the example and the comparative example. Elements other than the protrusion height of the first protrusion and the thickness of the first alignment film are common to the example and the comparative example. In the light control members of Examples and Comparative Examples, the first resin base and the second resin base are made of a 100-μm-thick polycarbonate resin, and the first alignment film and the second alignment film are made of a polyimide resin. The GH method is used for the liquid crystal layer. The bead spacer is made of an acrylic resin having a diameter of 9.0 μm. The first substrate and the second substrate are made of a 100 μm-thick polycarbonate resin, and the first bonding layer and the second bonding layer are made of a 20 μm-thick acrylic epoxy resin.

  The protrusion height of the first protrusion in the example is 0.3 μm, and the thickness of the first alignment film is 100 nm. Therefore, the ratio of the thickness of the first alignment film to the diameter of the bead spacer in the example is 5%. On the other hand, the protrusion height of the first protrusion in the comparative example is 0.7 μm, and the thickness of the first alignment film is 200 nm. Therefore, the ratio of the thickness of the first alignment film to the diameter of the bead spacer in the comparative example is 8%.

  In the light control unit of the example, the protrusion height of the first protrusion is smaller than that of the light control unit of the comparative example, and the thickness of the first alignment film is smaller. For this reason, in the light control unit of the example, the bead spacer is more likely to fall off from the first protrusion than in the light control unit of the comparative example. When actually confirmed using an optical microscope, it was confirmed that the alignment film of the light control unit of the example had circumferential protrusions that did not hold the bead spacers as traces of falling off. On the other hand, in the light control unit of the comparative example, no circumferential protrusion separated from the bead spacer was observed.

  No streak-like scratches or bubbles were observed in the field of view through the light control member having the light control unit of the example. This is considered to be because the aggregated bead spacers were dropped in the process of manufacturing the light control unit. On the other hand, streaks and bubbles were observed in the field of view through the light control member having the light control unit of the comparative example. This is considered to be because the aggregated bead spacer could not be dropped in the process of manufacturing the light control unit.

DESCRIPTION OF SYMBOLS 1 Automobile 5 Sunroof 10 Light control member 11 First substrate 12 Second substrate 13 First bonding layer 14 Second bonding layer 15 Wiring 20 Light control unit 25 Liquid crystal layer 27 Sealing material 30 First laminate 31 First resin base material 33 First alignment film 35 First protrusion 351 First holding protrusion 352 First non-holding protrusion 37 First electrode 40 Second laminate 41 Second resin base material 43 Second alignment film 47 Second electrode 50 Bead spacer

Claims (11)

A first laminate having a first resin base material and a first alignment film laminated on the first resin base material;
It has a second resin base material and a second alignment film laminated on the second resin base material, and is arranged such that the first alignment film and the second alignment film face each other. , A second laminate,
Liquid crystal molecules arranged between the first laminate and the second laminate, the orientation of which is controlled by applying a voltage to an electrode provided on at least one of the first laminate and the second laminate. A liquid crystal layer containing
A plurality of bead spacers disposed between the first laminate and the second laminate,
The first alignment film includes a plurality of first protrusions protruding toward the liquid crystal layer,
The dimming unit, wherein only a part of the first convex portion at least partially surrounds the bead spacer and holds the bead spacer.   2. The first protrusion includes a first holding protrusion that at least partially surrounds the bead spacer and holds the bead spacer, and a first non-holding protrusion separated from the bead spacer. 3. The dimming unit according to 1.   The light control unit according to claim 2, wherein the first non-holding convex portion linearly extends at least a part of a circumferential pattern.   4. The light control unit according to claim 3, wherein an area of a region surrounded by the peripheral pattern is at least 1.02 times an area of the bead spacer in a plan view. 5.   The dimming unit according to any one of claims 1 to 4, wherein a projection height of the first protrusion that holds the bead spacer is not less than 0.2 m and less than 0.5 m.   The light control according to any one of claims 1 to 5, wherein a projection height of the first protrusion other than the first protrusion that holds the bead spacer is not less than 0.2 µm and less than 0.5 µm. unit.   The light control unit according to any one of claims 1 to 6, wherein the thickness of the first alignment film is 60 nm or more and 150 nm or less.   The ratio of the protrusion height [μm] of the first convex portion holding the bead spacer to the diameter [μm] of the bead spacer is not less than 2.2% and less than 5.5%. The light control unit according to any one of the above. A pair of substrates,
A light control member, comprising: the light control unit according to any one of claims 1 to 8 disposed between the pair of substrates. Producing a first plate having a first resin substrate and a first alignment film laminated on the first resin substrate;
Supplying a liquid crystal material on the first plate;
Laminating a second plate material on the first plate material,
The method of manufacturing a light control unit, wherein the step of manufacturing the first plate member includes a step of fixing a bead spacer to the first alignment film and a step of dropping and removing a part of the bead spacer.   The method of manufacturing a light control unit according to claim 10, wherein, in the step of dropping and removing a part of the bead spacer, the bead spacer having low adhesion strength to the first alignment film is removed.

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