JP2019105679A - Dimming device - Google Patents

Abstract

To propose a configuration of a peripheral edge seal part effective for improving reliability and design property, when employing, as a principal part of a dimming device, a dimmer film using a transmitting-scattering type liquid crystal layer, in which a flexible resin film is used as a front substrate and a rear substrate.SOLUTION: A dimmer film installed on a transparent substrate includes a seal portion in which a sealant is applied so as to cover a side face exposing a laminate structure at a peripheral part thereof. The seal portion has a difference of color chromaticity a* each within a range of -10 to +10, and a difference of color chromaticity b* each within a range of -10 to +10 with regard to the dimmer film in a transparent state and a scattering state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light control film using a transmission-scattering type liquid crystal layer.

  The liquid crystal display device is used as a general display device in various regions such as an information display device such as a numerical value and an image display device such as a video.

  In a display device using these liquid crystal materials, liquid crystal molecules are aligned and sandwiched between substrates having electrodes arranged with a predetermined distance, and these are further sandwiched by two polarizing plates. By driving the liquid crystal to change the transmittance of polarized light, it is possible to perform display by modulation of light transmission state-light transmission state in cell (pixel) units.

  On the other hand, in areas such as windows in living spaces such as buildings and automobiles, examination of light control glass that gives the window glass an optical function to keep the living space comfortable according to changes in the external environment (For example, nonpatent literature 1).

  When a liquid crystal material is used for such a light control glass, unlike the above-described method for a display device, a polarizing plate is not used, and a liquid crystal transmission state as a liquid crystal display element with high light utilization efficiency There is a liquid crystal display element which performs switching between (transparent state) and scattering state (opaque state), which is disposed in a void formed inside a polymer network composed of a resin formed in a three-dimensional network shape. A polymer network liquid crystal (PNLC: Polymer Network Liquid Crystal) having a configuration having liquid crystal molecules, or a polymer dispersed liquid crystal (PDLC: Polymer Dispersed Liquid Crystal) having a configuration in which liquid crystal molecules are dispersed in a polymer Is known, and is employed as an element that produces a change in state of light transmission, not light transmission but light transmission.

  In general, the liquid crystal layer is easily degraded by acid, moisture, ultraviolet light, etc. In particular, the sheet end (peripheral portion) where the liquid crystal layer is held is highly likely to be exposed to moisture, acid, ultraviolet light, etc. Is easy to occur.

  As a proposal relating to the sealing structure of the peripheral edge of a PDLC panel in which PDLC is coated on the front substrate and the back substrate is laminated on this, in Patent Document 1, the front substrate, the side of the back substrate and the side of PDLC are disclosed And a sealing structure for applying a sealing agent.

  In Patent Document 1, as the characteristics required for the sealing agent, it is a solventless silicone adhesive having a viscosity of 100,000 to 500,000 CP, and the sealing agent is made similar to the color of the PDLC panel, and the sealing agent is used. It has been mentioned to make the presence of inconspicuous.

  In another form of the PDLC panel, the front substrate and the back substrate are held in a gap via a spacer, and a sealing agent is applied by printing or the like on the facing surface several mm around both substrates to form a panel Roll-to-roll (roll-to-roll) using a flexible resin film instead of a rigid substrate (glass, resin plate) in which both the front substrate and the back substrate are rigid (see, for example, Patent Document 2). Suggestions concerning forms suitable for manufacturing by the to roll method can be seen, but seal structures of the peripheral portion with characteristics and methods suitable for each are required.

Unexamined-Japanese-Patent No. 6-186574 International Publication No. 2017/146039

NEW GLASS Vol. 13 No. 1 1998 P48-51

  The present invention adopts a light control film using a flexible resin film as a front substrate and a back substrate as a main part of a light control apparatus, and is configured of a peripheral seal portion effective to improve reliability and design. The purpose is to propose

In the light control device according to the present invention, the light control layer capable of switching the haze in two or more steps according to the applied voltage is sandwiched by the transparent base film on which the transparent electrode for applying a voltage to the light control layer is formed. In a light control device using a light control film
The sealing portion is formed by coating and forming a sealing agent so as to cover the side surface where the laminated structure is exposed at the peripheral portion of the light control film disposed on the transparent substrate.
The seal portion has a difference in chromaticity a * between the transparent state and the light control film in the scattering state in the range of −10 to +10, respectively, and a difference in chromaticity b * is −10 to +10 respectively. It is characterized by being in the following range.

A plurality of the light control films are juxtaposed on the transparent substrate so that the haze can be switched independently.
There is also adopted a configuration having a seal portion formed by applying a sealing agent so as to fill the gaps between adjacent light control films and to cover the side surface where the laminated structure is exposed at the peripheral portion of each light control film.

  The seal portion having a thickness of 150 μm desirably has a degree of yellowness (YI value) of −10 or more and 10 or less within a range of 90% or more of light transmittance with respect to a wavelength of 550 nm.

  According to the present invention, the configuration of the peripheral seal portion effective for improving the reliability and design is proposed, and deterioration of the liquid crystal layer due to ultraviolet light is hard to occur, and high reliability can be realized, and the peripheral portion of the light control film Is provided, and a light control device with excellent designability is provided.

Sectional drawing which shows an example of the light modulation apparatus which concerns on embodiment of this invention. Sectional drawing which shows the other example of the light modulation apparatus which concerns on embodiment of this invention. The top view which shows the other example of the light modulation apparatus which concerns on embodiment of this invention. Explanatory drawing which shows the application example as a screen which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings, components having the same or similar function are denoted by the same reference numerals, and redundant description will be omitted. Each drawing shows an example of an embodiment of the present invention, and is not limited to these.

  FIG. 1 is a cross-sectional view showing an example of a light control device according to an embodiment of the present invention. The light control film 10 has a light control layer (liquid crystal layer) 13 and a flexible transparent film 11 on which a transparent electrode 12 is formed so as to sandwich both surfaces thereof. The peripheral portion of the light control film 10 is arranged The seal portion 14 is provided on the rigid transparent substrate 15.

  The material and the like of the transparent substrate 15 are not particularly limited, and can be appropriately selected according to the application. For example, although a sheet made of a glass plate, a sheet made of a resin material such as a polycarbonate resin or an acrylic resin, etc. may be used singly or as a composite material combining a plurality of sheets, it is not limited thereto. Further, the transparent substrate 15 may be provided with various functional layers such as a barrier layer in addition to a reflection layer and an absorption layer for ultraviolet rays, heat rays, electromagnetic waves and the like without any problem.

  Any transparent film 11 can be used as long as it is a substantially transparent film. Specifically, for example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate resins, acrylic resins, cellulose derivatives such as triacetyl cellulose (TAC), polyether sulfone (PES) Although the film which consists of resin, a polyimide resin, polyolefin resin, such as polyethylene and a polypropylene, etc. can be illustrated, it is not necessarily limited to these.

  An ultraviolet absorber, a stabilizer, etc. may be added to such a transparency film, and an ultraviolet ray absorption layer, a heat ray reflective layer, a barrier layer, etc. are provided on any surface of the transparency film. There is no problem even if

  In addition, the transparent film may be appropriately subjected to an easy adhesion treatment, an antistatic treatment, and the like, and may be provided with a reinforcing substrate or the like without any problem.

  Any transparent electrode 12 may be used as long as it is a conventionally known electrode material having transparency. For example, an indium tin oxide (ITO) conductive film, a tin oxide conductive film, a zinc oxide conductive film, a polymer conductive film Although the electrode which consists of etc. can be illustrated, it is not necessarily limited to these.

  Such a transparent electrode 12 is formed by using physical vapor deposition (PVD) such as vacuum evaporation or sputtering, various chemical vapor deposition (CVD), various coating methods, etc. Can.

  If desired, patterning of the transparent electrode 12 may be performed by any method such as an etching method, a lift-off method, a laser trimming method, or a method using various masks.

  An alignment film or the like may be provided on the transparent electrode 12 as appropriate. The alignment film may be either a horizontal alignment film or a vertical alignment film, as long as it is a conventionally known alignment film, and can be appropriately selected according to the application.

  In the present invention, any type of liquid crystal composition of PDLC and PNLC can be adopted as the light control layer 13.

  In the light control layer by PNLC, there is almost no unreacted component in phase separation, and the polymer network and the liquid crystal region behave like clearly separated with high purity.

  In addition, it is possible to realize an ideal alignment state without performing a pretilt alignment process by rubbing the substrate (conductive film), and the liquid crystal molecules are aligned almost uniformly in each domain divided by the polymer network. It will be.

  The driving voltage of PNLC generally depends on the structural characteristics of the polymer network (such as the size and shape of the domain, the film thickness of the polymer network, etc.), and the relationship between the structure of the polymer network and the obtained light transmission / scattering degree The drive voltage is determined at. In order to construct a PNLC that can obtain sufficient light transmission / scattering in a voltage range of 100 V or less, each domain should be uniform in size and uniform in size. Need to form a polymer network.

  In the present invention, the domain size depending on the polymer network structure is controlled to be 3 μm or less, preferably 2 μm or less, more preferably about 1 μm.

  As the polymer material, any of the conventionally known materials can be used, but a UV curable resin capable of inducing and curing a polymerization reaction by UV irradiation is suitably used.

  Specific examples thereof include, but are not limited to, various (meth) acrylate compounds such as urethane (meth) acrylate, epoxy (meth) acrylate and isobonyl (meth) acrylate.

  A polymerization initiator, a sensitizer, various stabilizers, etc. may be added to such an ultraviolet curable resin.

  The liquid crystal material may be any of known liquid crystal materials such as nematic liquid crystal, smectic liquid crystal, and cholesteric liquid crystal. Among them, in consideration of driving at a low voltage, scattering characteristics, and the like, it is preferable that the anisotropy of the dielectric constant is high and the anisotropy of the refractive index is large.

  Such a liquid crystal material may have a functional group such as ethylene group to be subjected to the polymerization reaction of the above-described polymer material, or may be previously introduced as a side chain into the polymer material before the polymerization reaction. It is good.

  A spacer may be introduced into the light control layer 13 as described above. By introducing the spacer, the thickness of the light control layer 13 can be kept uniform.

  Although it does not specifically limit as a spacer, A granular resin spacer, a granular glass spacer, etc. can be used suitably.

  As a method for providing the light control layer 13, a liquid crystal composition is coated on the transparent film having the transparent electrode using various coaters and the like, and then the transparent film having the other transparent electrode is laminated. A conventionally known method such as a method or a so-called ODF (One-Drop-Fill) method of dropping a liquid crystal composition can be arbitrarily used.

  A seal portion 14 for protecting the light control layer 13 from moisture, acid, ultraviolet light and the like is provided by coating on the peripheral portion of the light control film 10 obtained as described above.

  Examples of the material used for the sealing portion 14 include thermosetting resins in various resin systems such as epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, silicone resin, modified polymer, etc. Various resin materials such as mold, light curing type, moisture curing type and anaerobic curing type can be used.

  In the seal portion 14, the difference between the light control film 10 in the transparent state and the chromaticity a * in the scattering state is −10 or more and 10 or less in the hue, and the difference in the chromaticity b * is It is important that they are in the range of −10 to 10, respectively.

  In this way, the difference between the chromaticity of the light control film 10 and the chromaticity of the seal portion 14 even when the light control film 10 is in the transparent state or in the scattering state. It is possible to make the presence of the seal portion 14 less visible. Therefore, the design of the light control device obtained can be made extremely high. In addition, the seal portion 14 has a structure in which the seal portion 14 is extended not only to the side surface but also to the uppermost surface of the transparent film 11 at the peripheral portion of the light control film 10. The effect also improves.

  Although it is desirable that the seal portion 14 for obtaining such characteristics is substantially transparent, dyes, fillers and the like may be added as appropriate depending on the situation. In the case of adding a dye, in consideration of the weather resistance and the like, a pigment based dye is desirable.

  Here, the chromaticity a * and the chromaticity b * represent chromaticity indicating hue and saturation in the L * a * b * color system standardized by the International Commission on Illumination (CIE). Where + a * indicates red direction, -a * green direction, + b * yellow direction, -b * blue direction, and the larger the value, the brighter the color, and vice versa It shows that it becomes dull as it approaches the center.

  Moreover, the seal part 14 further has an ultraviolet shielding function, and when the film thickness of the seal part 14 is 150 μm, the transmittance of light with a wavelength of 380 nm (ultraviolet light) is in the range of 0% to 60%. This is very important.

  Thereby, it can prevent that the light control layer 13 degrades when an ultraviolet-ray injects from the peripheral part of the light control film 10. As shown in FIG.

  In order to obtain the seal portion 14 having such characteristics, it is desirable that a UV absorber be added to the sealing agent.

  As the UV absorber, any of conventionally known UV absorbers can be used arbitrarily. Specifically, for example, inorganic ultraviolet absorbers such as titanium oxide, zinc oxide and cerium oxide, and organic ultraviolet absorbers such as benzotriazole, triazine, benzophenone and the like are appropriately selected, and they may be used alone or in combination of two or more. It can be used as a mixture of

  By providing the sealing layer 14 as described above, it is possible to provide a highly reliable light control film 10 and a light control device with extremely high designability and suppressing problems such as deterioration.

  FIG. 2 shows an example in which two or more light control films 10 as described above are provided on a substrate 20, and a structure in which the above-mentioned seal portion 14 is provided between the peripheral portions of each light control film 10 is shown. It is shown.

  By providing the above-mentioned seal part 14 as shown in FIG. 2, even in the case where two or more light control films are juxtaposed, it is possible to make the seal part 14 less visible and improve the design Can. Even in the case of FIG. 2, the seal portion 14 is also in contact with the uppermost surface of the transparent film 11, and the effect of sealing the end face and adhesion with the substrate 20 is enhanced.

  FIG. 3 shows an example in which the AC power supply 31 and the control unit 32 are provided in the light control device 1.

  The AC power supply 31 is connected to the control unit 32, and the control unit 32 controls the voltage supplied (applied) to the transparent electrode 12 provided on the light control film 10.

  For example, by turning on or off the voltage applied to the light control film 10, the alignment state of the liquid crystal material in the light control layer 13 can be controlled, and the light control film 10 can be made transparent or scattering. It becomes possible to control the haze (whiteness) of the light control film.

  The light control device 1 obtained as described above can be used for various applications such as windows of buildings, windows of automobiles, sunroofs, partitions and the like.

  FIG. 4 shows an example in which the light control device 1 is used as a screen 41 for projecting an image projected from the projector 42.

  When the screen 41 is in the transparent state, it can be used as a transparent plate that does not disturb the view, and when it is in the scattering state, it can also be used as a partition.

  Furthermore, by projecting the image projected from the projector 42 to the part in the scattering state, it can be used as a screen.

  When two or more light control films are provided on the screen 41, only the area desired to be used as the screen can be in the scattering state, and the other parts can be in the transparent state. You can enjoy the image projected on the screen while you can get a glimpse of the back of the screen.

Hereinafter, the present invention will be specifically described by Examples and Comparative Examples in which the chromaticity difference (Δa *, Δb *), the light transmittance (550 nm), and the yellowness (YI value) are variously changed.
(1) Chromatic difference

Example 1
Two flexible resin film substrates having an ITO layer were prepared, and a 25 μm spacer was applied to one of the substrates. Thereafter, the following liquid crystal composition is dropped on the spacer coated surface by the ODF method, and then the other film substrate is bonded such that the ITO surfaces of the other film substrates face each other, and a metal halide lamp with an illuminance of 60 mW with a wavelength of 350 nm or less The ultraviolet ray irradiation of 7 J / cm < ² > was carried out in conversion of 365 nm using, and the liquid crystal display element used as a light control film was obtained. The inside of the irradiation apparatus at the time of irradiating an ultraviolet-ray to a liquid crystal cell was controlled at 25 degreeC.

 A transparent substrate with an adhesive material is laminated on this liquid crystal display element, half-cut at one end to electrically connect the electrode layers on both sides, a feed portion is formed (not shown), and the adjustment with a reinforcing base is performed I got a light film. Three light control films are attached at intervals of 5 mm and attached to blue plate glass, then the following sealing agent is applied to the gaps of the light control film, and the black light is irradiated until the tackiness of the surface disappears. Formed.

<Liquid crystal composition>
The liquid crystal composition contains a liquid crystal, a curable resin, a bifunctional monomer, and a monomer having at least one polar group selected from the group consisting of a hydroxy group, a carboxy group and a phosphoric acid group. As liquid crystals, nematic liquid crystals, smectic liquid crystals or cholesteric liquid crystals can be used.

Sealing agent
As the sealing agent, one prepared as a photocurable resin liquid containing a polythiol compound, a polyene compound having two or more carbon-carbon double bonds in one molecule, and a photopolymerization initiator may be used As polyene compounds, allyl compounds, propenyl compounds, (meth) acrylate compounds and the like can be mentioned, and polyene-polythiol resin, (meth) acrylate compounds can be used.

Examples 2 to 8
<Comparative Examples 1 to 6>
The composition (formulation) was variously changed, and all 14 types of sealing agents according to Examples 2 to 8 and Comparative Examples 1 to 6 having various combination data at values of a * and b * were prepared. The sample of the light control apparatus which formed the seal | sticker part on the same conditions was obtained.

  Table 1 shows the evaluation results of each sample based on the following evaluation means.

<Visual observation>
The samples were observed from a distance of 2 m for each of the samples when the light control film was in the transparent state and in the scattering state, and it was determined that the design was excellent when the gaps were not noticeable.

<Chromaticity measurement>
Using a "Spectrophotometer U-4100" manufactured by Hitachi High-Technologies, measure the chromaticity a * and the chromaticity b * of the encapsulant portion of each sample, and the light control film in the transparent state and scattering The difference (Δa *, Δb *) of each chromaticity from that in the state was determined.

(2) Light transmittance (550 nm), YI value The seal according to Examples 9-11 and Comparative Examples 7-9 having various combination data at 550 nm light transmittance and YI value by variously changing the composition (formulation) All six types of agents were produced, and the sample of the light control apparatus in which the seal part was formed on the same conditions as Example 1 was obtained.

  The evaluation results of each sample based on the following evaluation means are shown in Table 2.

<Visual observation>
For each sample, visual observation was performed to see if there was a change in the appearance of the seal after the black light irradiation. Those in which the color change was not noticeable were judged as OK products.

<550 nm light transmittance>
For each sample, the transmittance of light at 550 nm was measured using "Spectrophotometer U-4100" manufactured by Hitachi High-Technologies Corporation.

  From Table 1, when the gap portion provided with the seal portion is not noticeable when observed from a distance of 2 m, the chromaticity a *, b * of the seal portion, and the chromaticity a in the transparent state and the scattering state of the light control film A case where the difference between Δ and the chromaticity b * (Δa *, Δb *) is in the range of −10 or more and 10 or less, respectively, is judged as ○ (good).

  From Table 2, those with no change in the appearance of the sealed portion after black light irradiation have a 550 nm light transmittance of 90% or more and a YI value in the range of -10 or more and +10 or less. Good) It is judged.

DESCRIPTION OF SYMBOLS 1 ... Light control apparatus 10 ... Light control film 11 ... Transparency film 12 ... Transparent electrode 13 ... Light control layer 14 ... Seal part 20 ... Substrate 31 ... AC power supply part 32 ... Control part 41 ... Screen 42 ... Projector

Claims (3)

A light control film using a light control film in which a light control layer capable of switching the haze in two or more steps according to an applied voltage is sandwiched by a transparent base film on which a transparent electrode for applying a voltage to the light control layer is formed. In the light device,
The sealing portion is formed by coating and forming a sealing agent so as to cover the side surface where the laminated structure is exposed at the peripheral portion of the light control film disposed on the transparent substrate.
The seal portion has a difference in chromaticity a * between the transparent state and the light control film in the scattering state in the range of −10 to +10, respectively, and a difference in chromaticity b * is −10 to +10 respectively. The light control device characterized by being in the following range. A plurality of the light control films are juxtaposed on the transparent substrate so that the haze can be switched independently.
The light control device according to claim 1, further comprising: a seal portion formed by applying a sealing agent so as to fill the gaps between adjacent light control films and to cover the side surface where the laminated structure is exposed at the peripheral portion of each light control film. .   The seal portion having a thickness of 150 μm has a yellowness (YI value) of -10 or more and 10 or less within a range of 90% or more of light transmittance with respect to a wavelength of 550 nm. Light control device.

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