WO2000060409A1 - Gradateur a cristaux liquides - Google Patents

Gradateur a cristaux liquides Download PDF

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Publication number
WO2000060409A1
WO2000060409A1 PCT/JP2000/001874 JP0001874W WO0060409A1 WO 2000060409 A1 WO2000060409 A1 WO 2000060409A1 JP 0001874 W JP0001874 W JP 0001874W WO 0060409 A1 WO0060409 A1 WO 0060409A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
crystal material
dichroic dye
ratio
transparent conductive
Prior art date
Application number
PCT/JP2000/001874
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English (en)
Japanese (ja)
Other versions
WO2000060409A8 (fr
Inventor
Yuichi Yano
Original Assignee
Nippon Sheet Glass Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2000037384A external-priority patent/JP2000347223A/ja
Priority claimed from JP2000037347A external-priority patent/JP2000347222A/ja
Application filed by Nippon Sheet Glass Co., Ltd. filed Critical Nippon Sheet Glass Co., Ltd.
Publication of WO2000060409A1 publication Critical patent/WO2000060409A1/fr
Publication of WO2000060409A8 publication Critical patent/WO2000060409A8/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/13725—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on guest-host interaction

Definitions

  • the present invention relates to a liquid crystal light adjuster, and more particularly, to a liquid crystal light adjuster that can be used as a screen for blocking a visual field in a window or a partition of an automobile or a building, or as a curtain for controlling lighting.
  • liquid crystal dimmer having excellent durability and a dimming function that is easy to increase the area is disclosed in, for example, Japanese Patent Publication No. 58-501613.
  • NCA P Nematic Curvil inear Aligned Phase
  • Product dimmers are known.
  • These liquid crystal light adjusters operate based on the following principle.
  • the liquid crystal dimmer disclosed in the above-mentioned publication in which small droplets of a liquid crystal substance are dispersed in an inexpensive polymer has a curved surface of a polymer wall when no voltage is applied (hereinafter referred to as “when no voltage is applied”).
  • when no voltage is applied When the liquid crystal is aligned along the optical path, the optical path is twisted, and the light is reflected and scattered at the interface between the polymer and the liquid crystal droplets, so that it appears milky.
  • the liquid crystal in the liquid crystal droplet is arranged in the direction of the electric field by an external electric field, and the ordinary refractive index (no) of the liquid crystal and the refractive index of the polymer (np ),
  • the light incident perpendicular to the liquid crystal dimmer surface passes through the liquid crystal dimmer without reflection at the interface between the polymer and the polymer, so that the liquid crystal dimmer becomes transparent.
  • the degree of scattering of the incident light in the liquid crystal light adjuster is adjusted by the applied voltage. Therefore, when the liquid crystal light adjuster is used, for example, as a window of a building or a window of an automobile, its design may be significantly impaired.
  • Japanese Unexamined Patent Publication No. 3-66162 discloses a method in which a dichroic dye is added to a liquid crystal material used for a liquid crystal light adjuster, and the light is applied when no voltage is applied. A method for increasing light absorption is disclosed.
  • Japanese Patent Application Laid-Open No. Sho 58-5016-131 Japanese Patent Application Laid-Open No. Sho 60-520218 and Japanese Patent Laid-Open No. Hei 3-66162 are disclosed.
  • the liquid crystal light adjuster when no voltage is applied, light is scattered and absorbed, so that the visual field is blocked and darkened.
  • the liquid crystal light adjuster when a voltage is applied, the liquid crystal light adjuster is transparent, so that a transmitted image is clearly recognized and displayed, as in a normal transparent window, and a visual field can be secured.
  • Dimming bodies used as windows of automobiles or windows of buildings, partitions, etc. are required to have transparency and visibility when they are transparent, as in the case of conventional glass plates.
  • it is opaque there is a strong demand that the field of vision is sufficiently blocked to ensure privacy, and that it is necessary to block lighting.
  • the transmittance when no voltage is applied is reduced in order to improve the visual field control performance, the transmittance when a negative voltage is applied also decreases.
  • the haze ratio at the time of applying a voltage is increased, and the transparency is reduced.
  • the transmittance at the time of applying a voltage is increased, the transmittance at the time of applying no voltage is also increased, and sufficient visual field control ability cannot be obtained.
  • the change width of the visible light transmittance hereinafter referred to as “ ⁇ is”) is 30% or more, and the haze ratio is 10%. The following were not obtained:
  • the haze ratio indicates a ratio of scattered light to total transmitted light.
  • the opening When the liquid crystal light adjuster is used as a window or a partition of a building, the opening often has a large area of lm 2 or more. Since the liquid crystal dimmer is basically an electric drive type, the current consumption is small. However, when the area is 1 m 2 or more, the current consumption as one element increases considerably.
  • liquid crystal light adjusters in which a dichroic dye is added to the liquid crystal
  • the current consumption is larger than that of a liquid crystal dimmer without the liquid crystal.
  • the liquid crystal light adjuster to which the dichroic dye is added has a large change in the visible light transmittance when no voltage is applied and no voltage applied, and thus the visual field control performance is improved. This is because the resistance value is considered to be a state in which the impurities are increased and the resistance value is reduced.
  • the present invention has been made in view of the above-mentioned problems of the prior art, and a first object of the present invention is to provide a liquid crystal light control device which is easy to increase in area, and has excellent visual field control performance and transparency when voltage is applied. Is to provide.
  • a second object is to provide a highly reliable liquid crystal light modulator that can be easily increased in area and consumes less current.
  • the liquid crystal light adjuster according to the first invention of the present invention is characterized in that a transparent conductive film is provided on each of opposing surfaces of a pair of transparent substrates, and a liquid crystal material and a dichroic color that is oriented according to the orientation of the liquid crystal material.
  • ⁇ the absorbance of the dichroic dye in the major axis direction (hereinafter referred to as “ ⁇ ”) and the minor axis direction (hereinafter referred to as “ ⁇ ⁇ ”) satisfy the following formula (1). It is characterized by.
  • Adjustment of liquid crystal dimmer performance can be done by selecting several factors that make up the liquid crystal dimmer: In other words, the following five points are the most effective ways to increase ⁇ is.
  • S is represented by the following formula (2), and indicates the parallelism of the dye molecule absorption axis with respect to the alignment direction of the liquid crystal molecules. Practically, it is an amount that controls the display contrast of the liquid crystal element. As S approaches 1, a brighter and clearer display becomes possible.
  • the methods 3) and 5) above require the application of a larger voltage, so that the same applied voltage reduces the transmittance when the voltage is applied and increases the haze rate.
  • the haze ratio at the time of applying a voltage increases as ⁇ increases.
  • the method 1) can increase ⁇ is without a decrease in transmittance due to a decrease in transmittance at the time of applying a voltage and a decrease in haze ratio.
  • ⁇ when S is less than 0.75, ⁇ also decreases with a decrease in S, which decreases the light absorption performance of the dye, thereby increasing the visible light transmittance when no voltage is applied. As a result, ⁇ i s does not exceed 29%.
  • ⁇ is 30% or more.
  • ⁇ is 30% or more.
  • ⁇ n is represented by the following equation (3), where n o is the ordinary refractive index of the liquid crystal material and ne is the extraordinary refractive index of the liquid crystal material.
  • a transparent conductive film is provided on each of opposing surfaces of a pair of transparent substrates, and a liquid crystal material and a dichroic dye that is oriented according to the orientation of the liquid crystal material are held therein.
  • Liquid crystal light adjuster having a medium formed between the transparent conductive films, A mixing ratio of the liquid crystal material (hereinafter referred to as a “liquid crystal ratio”) is 50 wt% or more, a concentration ratio of the dichroic dye to the liquid crystal material is 1% or more, and Is in the range of 10 to 40 ⁇ m.
  • the liquid crystal ratio outside the range of the present invention is less than 50 wt%, the amount of the liquid crystal unit and the amount of the interface between the liquid crystal and the polymer decrease, so that the scattered light decreases. Accordingly, the distance of light passing through the dye is shortened, and the amount of absorbed light is also reduced, so that the visible light transmittance when no voltage is applied increases. On the other hand, the visible light transmittance when voltage is applied hardly changes. As a result, the change width of the visible light transmittance is small, and sufficient visual field control performance cannot be obtained. Further, when the concentration ratio of the dichroic dye is less than lwt%, the light absorption performance of color ⁇ is reduced, so that the visible light transmittance is also reduced, and sufficient visual field control performance cannot be obtained.
  • liquid crystal ratio it is difficult to increase the liquid crystal ratio to more than 80 wt% in order to secure adhesion to the transparent conductive film, optical uniformity, physical durability, and the like. It is preferable to be ⁇ %.
  • the concentration ratio of the dichroic dye to the liquid crystal material is excessively large, the visible light transmittance when voltage is applied becomes too low, and it becomes difficult to secure a sufficient visual field. It is preferably set to wt%.
  • the liquid crystal material used in the present invention is not particularly limited, but is preferably a nematic liquid crystal, a cholesteric liquid crystal, or a smectic liquid crystal. Among them, a nematic liquid crystal is preferable, and a nematic liquid crystal having a positive dielectric anisotropy is particularly preferable.
  • dichroic dyes examples include anthraquinone dyes and diazo dyes.
  • the medium (polymer) that holds the liquid crystal material is a material that is selected so that the refractive index (n) of the medium matches the ordinary light refractive index (no) of the liquid crystal material, and partitions the liquid crystal into multiple volumes. What is necessary is just to hold
  • the latex described in Japanese Patent Application Laid-Open No. 60-252687 is a suitable material, and has good adhesiveness to a substrate (transparent conductive film), optical uniformity, and physical durability. It is possible to provide an excellent liquid crystal light adjuster.
  • a substrate with a transparent conductive film used in the present invention a glass plate or a plastic film having an indium tin oxide (ITO) film or a tin oxide (Sn ⁇ 2 ) film formed on the surface is applied. be able to.
  • ITO indium tin oxide
  • Sn ⁇ 2 tin oxide
  • the liquid crystal light adjuster of the present invention is, in particular, a liquid crystal material having a birefringence ( ⁇ ) of 0.15 or less, an absorbance in the long axis direction of the molecule ( ⁇ ) and an absorbance in the short axis direction of the molecule ( ⁇ ⁇ ). ⁇ 0.7 (( ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ) / (A // + 2A ⁇ )) ⁇ 0.75
  • the ratio is at least 50 wt%
  • the concentration ratio of the dichroic dye to the liquid crystal material is at least 1 wt%
  • the distance between the transparent conductive films is within the range of 10 to 40 m. It is preferable that it is constituted.
  • the liquid crystal light adjuster of the present invention is produced, for example, by the following method.
  • a liquid crystal substance and an aqueous phase are mixed to form an emulsion, and the emulsion is added to a latex, or a liquid crystal substance and a latex are directly mixed to form an emulsion.
  • a surfactant in order to form stable liquid crystal particles.
  • Mixing is performed with various mixers such as a blender and a colloid mill.
  • a crosslinking agent is added to crosslink the latex to form a medium, Then, the medium is applied to a transparent substrate on which a transparent conductive film is formed by a knife blade or other suitable means, and dried. Then, it is bonded to another transparent substrate with a transparent conductive film to obtain a liquid crystal light adjuster.
  • surfactant 0.5 wt% of IGE PAL CO-610 (manufactured by GAF) was added, and they were added with 40 wt% of latex particles so that the liquid crystal ratio became 60 wl;%.
  • GAF dichroic dye
  • Zeneca Manufactured by Zeneca
  • crosslinking agent CX-100 manufactured by Zeneki Co., Ltd.
  • This mixture was indium tin oxide using a Doc Yuichi blade.
  • the film was coated on a polyethylene terephthalate (PET) film on which a (ITO) film had been previously coated and dried. After drying, another PET film with an ITO film and a laminated liquid light conditioner were obtained.
  • the thickness (distance between the transparent conductive films) was 25 zm.
  • a voltage of sine wave / 100 V / 50 Hz was applied to the liquid crystal dimmer thus obtained, and the performance was measured.As a result, ⁇ is 30% and the haze ratio was 8%. there were. Therefore, a liquid product dimmer having sufficient visual field control performance and sufficient transparency when voltage is applied was obtained.
  • the film was applied on a polyethylene terephthalate (PET) film on which a (ITO) film had been previously coated and dried. After drying, another PET film with an ITO film and a laminated liquid crystal light modulator were obtained.
  • the thickness (the distance between the transparent conductive films) was 25 m.
  • Activator I GEPAL CO-610 manufactured by GAF was added in an amount of 0.5 wt%, and they were mixed with 40 wt% of latex particles to obtain a liquid crystal ratio of 60 wt%.
  • GAF Greeneca
  • the crosslinking agent CX-100 manufactured by Zeneki Co., Ltd.
  • PET polyethylene terephthalate
  • surfactant I GEPAL CO-610 GAF
  • a cross-linking agent CX-100 manufactured by Generic Corporation was added at a ratio of 3 wt% to R-967 while slowly mixing.
  • the mixture was applied to a polyethylene terephthalate (PET) film previously coated with an indium tin oxide (IT ⁇ ) film using a doctor blade and dried. After drying, another PET film with an IT ⁇ film was laminated and a liquid crystal light modulator was obtained. Thickness (distance between transparent conductive films) is 15
  • a voltage of sine wave of 100 VZ and 50 Hz was applied to the liquid crystal dimmer thus obtained, and the performance was measured. Value.
  • the current consumption was 0.15 A / m 2 , no deterioration due to continuous energization or electrode breakdown due to voltage application was observed, and a liquid crystal light modulator with sufficient reliability was obtained.
  • the crosslinking agent CX-100 (manufactured by Zeneki Co., Ltd.) was added to the R-966 at a ratio of 3 wt% with gentle mixing. Using a doctor blade, this mixture is indium tin oxide
  • PET polyethylene terephthalate
  • ⁇ of the liquid crystal material is 0.15 or less, and the absorbance of the dichroic dye in the molecular long axis direction ( ⁇ ⁇ ) and the absorbance ( ⁇ ⁇ ) in the minor axis direction of the molecule satisfy 1.0 (( ⁇ - ⁇ ) Z (A // + 2A ⁇ )) ⁇ 0.75
  • a liquid crystal light modulator composed of: ⁇ ⁇ ⁇ is 30% or more, and has a light control performance of a haze ratio of 10% or less, so that it has excellent visual field control performance and transparency when voltage is applied, and A large-area liquid crystal light modulator can be obtained easily and at low cost.
  • the liquid crystal light adjuster according to the second invention of the present invention has a liquid crystal ratio of 50 wt% or more, a dichroic dye concentration ratio to a liquid crystal material of 1 wt% or more, and the transparent conductive material.
  • a liquid crystal dimmer configured so that the distance between the films is in the range of 10 to 40 / im, and the above configuration can ensure a current consumption (I) ⁇ 0.2 Zm 2 , thereby improving reliability.
  • I current consumption
  • liquid crystal light control device of the present invention When used as, for example, a window of an automobile, a window of a building, a screen for blocking a view in a partition, or a curtain for lighting control, a liquid crystal light control having a laminated glass function is provided. It can be glass.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Liquid Crystal (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)

Abstract

L'invention concerne un gradateur à cristaux liquides dans lequel des films conducteurs transparents sont prévus sur les faces opposées d'une paire de substrats transparents et dans lequel un milieu contenant un matériau à cristaux liquides ainsi qu'un colorant dichroïque aligné selon l'alignement du matériau à cristaux liquides. L'indice de double réfraction (Δn) du matériau à cristaux liquides est inférieur à 0,15. La relation entre l'absorptance (A//) le long de l'axe principal de la molécule de colorant dichroïque et l'absorptance (A ) le long de l'axe mineur de celle-ci, est exprimée par 1,0≥[A//-A )/(A//+2a )]≥0,75. L'invention porte sur un autre gradateur à cristaux liquides dans lequel le rapport (teneur en cristaux liquides) entre le matériau à cristaux liquides et le milieu est de 50 % en poids ou plus, le rapport entre la concentration de colorant dichroïque et celle du cristal liquide est de 1 % ou plus, et la distance entre les films conducteurs transparents est de l'ordre de 10 à 40 νm.
PCT/JP2000/001874 1999-04-02 2000-03-27 Gradateur a cristaux liquides WO2000060409A1 (fr)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
JP9643999 1999-04-02
JP9601399 1999-04-02
JP11/96439 1999-04-02
JP11/96013 1999-04-02
JP2000/37347 2000-02-16
JP2000037384A JP2000347223A (ja) 1999-04-02 2000-02-16 液晶調光体
JP2000/37384 2000-02-16
JP2000037347A JP2000347222A (ja) 1999-04-02 2000-02-16 液晶調光体

Publications (2)

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WO2000060409A1 true WO2000060409A1 (fr) 2000-10-12
WO2000060409A8 WO2000060409A8 (fr) 2000-11-23

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4556289A (en) * 1983-03-21 1985-12-03 Manchester R & D Partnership Low birefringence encapsulated liquid crystal and optical shutter using same
JPH01299022A (ja) * 1988-05-28 1989-12-01 Takiron Co Ltd 調光材用シート、調光材及びその製造方法
EP0409442A2 (fr) * 1989-07-20 1991-01-23 Raychem Corporation Dispositif à cristal liquide encapsulé à trouble réduit lors d'observation oblique commandé par une source de signaux sinusoidaux
JPH05112780A (ja) * 1991-10-23 1993-05-07 Mitsubishi Kasei Corp 調光材料およびそれを含む調光素子
JPH09143472A (ja) * 1995-09-18 1997-06-03 Mitsubishi Chem Corp 液晶組成物

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4556289A (en) * 1983-03-21 1985-12-03 Manchester R & D Partnership Low birefringence encapsulated liquid crystal and optical shutter using same
JPH01299022A (ja) * 1988-05-28 1989-12-01 Takiron Co Ltd 調光材用シート、調光材及びその製造方法
EP0409442A2 (fr) * 1989-07-20 1991-01-23 Raychem Corporation Dispositif à cristal liquide encapsulé à trouble réduit lors d'observation oblique commandé par une source de signaux sinusoidaux
JPH05112780A (ja) * 1991-10-23 1993-05-07 Mitsubishi Kasei Corp 調光材料およびそれを含む調光素子
JPH09143472A (ja) * 1995-09-18 1997-06-03 Mitsubishi Chem Corp 液晶組成物

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WO2000060409A8 (fr) 2000-11-23

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