WO2018009174A1 - Affichage de microgouttelettes de cristaux liquides basse tension et stable aux uv - Google Patents

Affichage de microgouttelettes de cristaux liquides basse tension et stable aux uv Download PDF

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Publication number
WO2018009174A1
WO2018009174A1 PCT/US2016/041058 US2016041058W WO2018009174A1 WO 2018009174 A1 WO2018009174 A1 WO 2018009174A1 US 2016041058 W US2016041058 W US 2016041058W WO 2018009174 A1 WO2018009174 A1 WO 2018009174A1
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Prior art keywords
liquid crystal
polymer
lcmd
polymer matrix
film
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PCT/US2016/041058
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English (en)
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Jiansheng Wang
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Jiansheng Wang
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Priority to CA3019756A priority Critical patent/CA3019756C/fr
Priority to PCT/US2016/041058 priority patent/WO2018009174A1/fr
Publication of WO2018009174A1 publication Critical patent/WO2018009174A1/fr

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    • 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
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
    • 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
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/08—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 light absorbing layer
    • G02F2201/086—UV absorbing

Definitions

  • This invention relates to a Liquid Crystal Micro-Droplet (LCMD) displays. More particularly, a display that is protected from ultraviolet radiation and that requires lower voltage to switch the liquid crystal and methods of making are provided.
  • LCMD Liquid Crystal Micro-Droplet
  • liquid crystal microdroplet LCMD
  • liquid crystal (LC) material is contained in microdroplets embedded in a solid polymer matrix. Birefringence results from a material having a different index of refraction in different directions.
  • the extraordinary index of refraction (n e ) of a liquid crystal molecule is defined as that measured along the long axis of the molecule, and the ordinary index of refraction (n 0 ) is measured in a plane perpendicular to the long axis.
  • Liquid crystals having a positive dielectric anisotropy ( ⁇ > 0) are called positive-type liquid crystals, or positive liquid crystals
  • liquid crystals having a negative dielectric anisotropy ( ⁇ ⁇ 0) are called negative-type liquid crystals, or negative liquid crystals.
  • the positive liquid crystals orient in the direction of an electric field, whereas the negative liquid crystals orient perpendicular to an electric field.
  • One approach to obtaining dispersed microdroplets in a polymer matrix is the method of encapsulating or emulsifying the liquid crystals and suspending the liquid crystals in a film which is polymerized.
  • This approach is described, for example, in U.S. Pat. Nos. 4,435,047; 4,605,284; and 4,707,080.
  • This process includes mixing positive liquid crystals and encapsulating material, in which the liquid crystals are insoluble, and permitting formation of discrete capsules containing the liquid crystals.
  • the emulsion is cast on a substrate, which is precoated with a transparent electrode, such as an indium tin oxide (ITO) coating, to form an encapsulated liquid crystal device.
  • ITO indium tin oxide
  • LCMD displays may also be formed by phase separation of low-molecular weight liquid crystals from a prepolymer or polymer solution to form microdroplets of liquid crystals.
  • This process described in U.S. Pat. Nos. 4,685,771 and 4,688,900, includes dissolving positive liquid crystals in an uncured resin and then sandwiching the mixture between two substrates, which are precoated with transparent electrodes. The resin is then cured so that microdroplets of liquid crystals are formed and uniformly dispersed in the cured resin to form a polymer dispersed liquid crystal device.
  • the positive liquid crystals in microdroplets are oriented and the display is transparent if the refractive index of the polymer matrix (n p ) is made to equal the ordinary index of liquid crystals (n 0 ).
  • the display scatters light in the absence of the electric field, because the directors (vector in the direction of the long axis of the molecules) of the liquid crystals are random and the refractive index of the polymer cannot match the index of the liquid crystals.
  • Nematic liquid crystals having a positive dielectric anisotropy ( ⁇ > 0), large ⁇ , which may contain a dichroic dye mixture, can be used to form a transparent and absorbing mode.
  • LCMD displays may be characterized as normal mode or reverse mode displays.
  • a normal mode display containing liquid crystals is non-transparent (scattering or absorbing) in the absence of an electric field and is transparent in the presence of an applied electric field.
  • a reverse mode display is transparent in the absence of an electric field and is non-transparent (scattering or absorbing) in the presence of an applied electric field.
  • liquid crystals in microdroplets are not entirely perpendicular to the substrate.
  • the central part of liquid crystals in the droplets is clear if the refractive index of the polymer matches the ordinary refractive index of the liquid crystals (n 0 ).
  • liquid crystals near the ends of the microdroplet are strongly bent because they are parallel to the skin of the inner layer. They are, therefore, tilted to the substrate surface, and the refractive index of the liquid crystals cannot match with the refractive indexes of the polymer matrix and inner layer. Therefore, parts of the liquid crystal droplets scatter light and produce haze.
  • compositions and methods for making LCMD devices that are highly resistant to deterioration by UV radiation.
  • Compositions and methods for making LCMD devices that require lower voltage than prior art devices to switch the liquid crystal are also provided.
  • FIG. 1 is a cross-sectional view of an LCMD film structure according to an embodiment of the present disclosure with added UV absorber.
  • FIG. 2 is a cross-sectional view of an LCMD film apparatus with cages of framework polymer in the liquid crystal polymer matrix according to one or more embodiments of the present disclosure.
  • FIG. 3 shows the UVA spectrum of benzotriazoles.
  • FIG. 4 shows a comparison of electric-optical curves (transmissibility vs AC driving voltage) among LCMD films made by different technologies.
  • first and second features are formed in direct contact
  • additional features may be formed between the first and second features, such that the first and second features may not be in direct contact
  • present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
  • LCMD device or “LCMD film” or “LCMD display” means a device or film or display, respectively, formed using various classes of polymer films.
  • an LCMD device may be formed using nematic curvilinear aligned phase (NCAP) films, such as material and devices described in U.S. 4,435,047 filed September 16, 1981 disclosing "Encapsulated Liquid Crystal and Method," which is incorporated by reference herein in its entirety.
  • NCAP nematic curvilinear aligned phase
  • An LCMD device may also be formed using polymer dispersed liquid crystal (PDLC) films formed using phase separation in a homogenous polymer matrix, such as material and devices described in U.S.
  • PDLC polymer dispersed liquid crystal
  • An LCMD device may also be formed using a non-homogenous polymer dispersed liquid crystal display (NPD-LCD) formed using a non-homogenous light transmissive copolymer matrix with dispersed droplets of liquid crystal material, such as material and devices described in U.S. Pat. No. 5,270,843 filed August 31, 1992 disclosing "Directly Formed Polymer Dispersed Liquid Crystal Light Shutter Displays," which is incorporated by reference herein in its entirety.
  • NPD-LCD non-homogenous polymer dispersed liquid crystal display
  • Other forms of liquid crystal microdroplet films may also be suitable.
  • a NPD-LCD device may be configured in one of two modes. In a positive mode, an NPD-LCD device is switchable between an opaque state without an applied electrical voltage and clear state with an applied electrical voltage. In a negative mode, an NPD-LCD device is switchable between a clear state without an applied electrical voltage and an opaque state with an applied electrical voltage.
  • LCMD film is often laminated between two pieces of glass by using an "interlayer,” which is a soft film material that may have an adhesion function when melted at a high temperature.
  • Interlayer is a thermoplastic material which may be used to bond glass or plastic or film together through a high-temperature process, called “interlayer lamination.”
  • interlayer lamination Sometimes, both interlayer material or interlayer film before being used in a lamination and an internal layer formed with the interlayer material after a lamination process are called “interlayer” in the glass industry.
  • Such interlayer-laminated LCMD panel may is used as privacy glass or a projection panel.
  • Microdroplet Display is written as USLV-LCMD.
  • switchable panel means a device or panel component formed of at least one layer of a transparent material such as glass or a polymer material together with at least one layer of liquid crystal microdroplets dispersed in a polymer matrix.
  • film is understood to include traditional polymer based film, such as polyester film and acrylic film and polycarbonate film, which have a relatively flexible planar or curved format.
  • glass is understood to include traditional silica-based glass as well as polymer-based transparent materials, such as acrylic glass and polycarbonate glass, which have a relatively rigid planar or curved format.
  • Film or glass may be colored or include tinting. Glass may also include reinforced, toughened and laminated glasses or any other type of transparent material having higher strength, safety or other special features, such as self-cleaning. Glass may also have an anti-reflective coating or anti-glare coating on it.
  • UV stable LCMD panel film structure 100 includes film layer 110, transparent and conductive coating 120 (e.g., an indium tin oxide (ITO) coating) and liquid crystal polymer matrix 140 which contain liquid crystal microdroplets 150 and polymer matrix 130.
  • transparent and conductive coating 120 e.g., an indium tin oxide (ITO) coating
  • liquid crystal polymer matrix 140 which contain liquid crystal microdroplets 150 and polymer matrix 130.
  • Liquid crystal microdroplets 150 and polymer matrix 130 may contain UV absorber(s), separately or together.
  • Film 110 may contain UV absorber, too.
  • USLV-LCMD film 200 structure includes film layer 110, transparent and conductive coating 120 (e.g., an indium tin oxide (ITO) coating) and liquid crystal polymer matrix 140 which contain liquid crystal microdroplet 150 and polymer matrix 130.
  • ITO indium tin oxide
  • Liquid crystal droplet microdroplet 150, polymer matrix 130 and film 110 may contain UV absorber(s), separately or together.
  • the polymer in the polymer matrix 140 is a copolymer including framework polymer 210.
  • the framework polymer 210 divides the entire liquid crystal into basically identical sizes of microdroplets 150.
  • UV light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays—that is, in the range between 400 nm and 10 nm, corresponding to photon energies from 3 eV to 124 eV.
  • UV light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays—that is, in the range between 400 nm and 10 nm, corresponding to photon energies from 3 eV to 124 eV.
  • Many natural and synthetic polymers are attacked by ultra-violet radiation and products made using these materials may crack or disintegrate (if they're not UV-stable). The problem is known as UV degradation, and it is a common problem in products exposed to sunlight.
  • UV stabilizers are used frequently in plastics, including cosmetics, inks and films.
  • UV stabilizers such as benzophenones
  • UV absorbers have been used in some areas, such as for plastic, to increase material stability under UV or sunlight exposure. The UV absorbers dissipate the absorbed light energy from UV rays as heat by reversible intramolecular proton transfer. This reduces the absorption of UV rays by the polymer matrix and hence reduces the rate of weathering.
  • Typical UV-absorbers are oxanilides for polyamides, benzophenones for PVC, benzotriazoles and hydroxyphenyltriazines for polycarbonate. Some existing UV absorbers may be used to protect LCMD and modified UV absorbers may be particularly useful and suitable for improving the anti-UV capability of LCMD and other LCDs.
  • thermos-absorbers such as organosulfur compounds.
  • Organosulfur compounds are efficient hydroperoxide decomposers, which thermally stabilize the polymers.
  • LCMD film comprises three parts to which UV absorbers may be added into liquid crystal microdroplets 150, polymer matrix 130 and film 110. UV absorber(s) may be added into each of these components. Since liquid crystal polymer matrix 140 is formed by a phase separation from a solution of PD-LCD or PDLC, UV absorbers may be added into a formula for making LCMD. For NCAP, UV absorber(s) may be added into the emulsion for making NCAP.
  • UV absorbers include the following products. Stabilizers for polymers are used singly or in combinations to prevent the oxidation, chain fission, uncontrolled recombinations and cross-linking reactions that are caused by photo-oxidation of polymers. Polymers become weathered by the direct or indirect impact of heat and ultraviolet light. UV absorbers dissipate the absorbed light energy from UV rays as heat by reversible intramolecular proton transfer. This reduces the absorption of UV rays by the polymer matrix and liquid crystal droplets and hence reduces the rate of weathering. Following are some UV absorbers.
  • UV absorbers Although many UV absorbers are commercially available, only a few of them are suitable for LCMD application without reducing the performance of an LCMD device, because LCMD is very sensitive to the UV-absorber's molecular structure, physical properties and chemical stability in the liquid crystal environment.
  • a UV absorber added into an LCMD system must have molecular structures similar to the structure of liquid crystals. Otherwise, the LCMD system will treat the UV absorbers as an impurity, which reduces performance, such as narrowing the application temperature range. UV absorbers having similar structures to the liquid crystal are suitable to add into LCMD at higher concentrations without affecting optical performance. If the structures of UV absorbers are different from the structures of liquid crystals, the absorber may reduce or destroy the optical function of the LCMD material.
  • nematic liquid crystals used in LCMD have a characteristic of molecular structure, or a rod like structure having a "body” and “tail".
  • the body may have some degree of polarity or induced polarity.
  • the body is usually formed by rigid rings, and the tail is formed by a flexible aliphatic chain.
  • the components of Merck liquid crystal E7 have the following structure:
  • Liquid crystals E7 is widely used in the study of LCD. It offers a range of operating temperatures. It exhibits a nematic phase from -62 °C to +58 °C and contains the following compounds at the listed percentage compositions shown.
  • a simple way to protect organic material against UV light is to prevent UV absorption, i.e. reducing the amount of light absorbed by chromophores.
  • This can be achieved by incorporating UV absorbers in the adhesives, which function by preferentially absorbing harmful utraviolet radiation and dissipating it as thermal energy.
  • Such stabilizers function according to the Beer Lambert law, which specifies that the amount of UV radiation absorbed is a function of both sample thickness and stabilizer concentration.
  • high concentrations of absorbers and sufficient thickness of the polymer are required before enough absorption takes place to effectively retard photodegradation.
  • Benzophenone and benzotriazole are the main UV absorbers used in adhesives and sealants.
  • Benzotriazole Benzophenone [0031] The different substituents in the benzotriazole group affect various properties, such as polarity, volatility, compatibility, physical condition and - last but not least - maximum absorption levels. Typical UV absorption spectra of benzotriazoles can be seen in illustration below.
  • UV range between 295 and 400 nm and a large reduction in absorption in the visible range above 400 nm.
  • the typical protection mechanism of benzotriazoles and benzophenones are illustrated in the shemes below.
  • UV absorption causes the electron density to move from the phenolic oxygen to the nitrogen atom.
  • the nitrogen becomes more alkaline than the oxygen as a result and a proton transfer occurs.
  • This mesomeric form represents an excited state, which stabilizes as a result of a radiationless transition to the ground state.
  • a substituent may be on each or both benzene rings of benzophenone.
  • the substituent may have different length of chain containing 1 carbon to 18 carbons at different position on the benzene ring.
  • other UV absorbers with a rod like shape may be used as base molecules to design UV-stabilizer liquid crystals.
  • the absorbers may be automatically distributed into both liquid crystal microdroplet 150 and polymer matrix 130, because phase separation cannot make any component 100% out of solid phase. Therefore, both liquid (crystal) phase and solid (polymer rich) phase contain the UV absorbers. In this way, the entire liquid crystal polymer matrix 140 is protected by UV absorbers.
  • this method is not suitable for industrial mass production or for using film as substrate, because it requires very high temperature (above 300 °C) to melt polymers.
  • this method indicates that it is possible to make highly identical sizes of droplets while providing the same environments around droplets and the resulting LCMD requires very low driving voltage.
  • V s switching or driving voltage for a bipolar droplet
  • d is sample thickness
  • a is the droplet radius
  • / is the droplet aspect ratio
  • K is the mean elastic constant of the liquid crystal
  • p p and p lc are the resistivities of polymer and liquid crystal regions respectively
  • ⁇ is the dielectic anisotropy of the liquid crystal. All droplets in an LCMD do not switch simultaneously because of different droplet sizes and shapes.
  • phase separation currently occurring in NPD-LCD or PDLC systems cannot provide low enough driving voltage. From phase separation diagrams, we know that droplet size is related to the surrounding condition, such as concentrations of components. Liquid centers generated at different times have different surrounding conditions. This causes different droplet sizes.
  • the present disclosure shows a novel method which may effectively control droplets to almost identical sizes; therefore, the LCMD requires very low voltage to drive and has a very steep voltage/transmission curve or electro-optical (E-O) curve.
  • dissolved framework polymer in the curing process.
  • monomers gradually undergo a polymerization to extend their chain length, causing the viscosity to gradually increase and the solubility to gradually decrease.
  • the system creates many phase separation centers to form LC droplets, which start at different times and different locations. The earlier started centers have more chance to grow bigger or merge, because the viscosity, time and adjacent material resource are more favorable, but the later-started liquid centers have less chance to grow. Therefore, a wide range of droplet sizes is formed during the entire period of phase separation and curing.
  • polymers are not easily dissolved, but it depends on solubility between solute and solvent.
  • acrylic glass or poly(methyl methacrylate) may be dissolved into the solvent chloroform.
  • a solution of poly(methyl methacrylate) and chloroform may be a transparent jelly. When some solvent chloroform is evaporated from the solution slowly, the jelly becomes thicker but still remains transparent. This indicates that poly(methyl methacrylate) may form a chloroform solution in any concentration.
  • Another example is gelatinized starch jelly. Like many other polymers, starch is in crystalline form. Crystalline regions do not allow water entry. Hot water may break down the intermolecular bonds of starch molecules and allow the hydrogen bonding sites to engage more water. Heat causes crystalline regions to become smaller, so that the chains begin to separate into an amorphous form.
  • LCMD Formation of LCMD involves multi components, including liquid crystals and monomers or oligomers.
  • Liquid crystals usually consist of four to ten different molecules.
  • the multicomponent system may undergo a simple phase separation with only two phases or liquid and solid phase. Liquid crystal droplets are in the liquid phase and the polymer matrix is the solid phase.
  • the multi-component system may be designed to have a complex phase separation temporarily involving three phases, mother solution, liquid droplet and solid polymer, in its process of phase separation.
  • a solution of liquid crystals and monomers may generate two new phases or liquid crystal droplets and solid polymer separated from mother solution. This complex phase separation may prevent liquid crystal droplets from merging, thereby controlling the size of liquid crystal droplets. Therefore, it has an important advantage in improving the quality of LCMD devices.
  • some special compounds are designed and selected to form a polymer which may be dissolved in the mother solution.
  • a high reactivity is needed to ensure forming a polymer faster than other components.
  • the reactivity difference among aromatic epoxy and aliphatic epoxy and the epoxycyclohexyl group may be utilized for this purpose.
  • Multiple reactive functional groups may act like centers of cross-link.
  • the amount of compounds with multi-functional groups is critical.
  • a long flexible chain is favorable to form jelly type of polymer matrix. High cross linking may result an earlier phase separation to occur.
  • a non-reactive functional group may help improve solubility, which is very important in this process. Since this is a liquid crystal mixture, the non-reactive functional group may be selected to be the same or a close functional group to that in liquid crystals. These requirements are favorable to form a polymer long chain which has a high solubility in the mother solution.
  • the following commercially available compounds have the mentioned features.
  • a newly formed polymer may have a high solubility to its mother solution containing liquid crystals and other monomers. High temperature is favorable to dissolve the newly formed polymer into the mother solution. It is possible that first phase separation may occur to form a new solid phase. Early-formed solid phase is similar to gelatinized starch distributed in water. During phase separation, the mother solution acts as a plasticizer. Liquid crystals and monomers are absorbed in the amorphous space of newly-formed polymer, which leads to a swelling phenomenon under a raised temperature to prevent forming crystalline regions in the structure of the newly formed polymer. For example, components in the mother solution enter tightly bound amorphous regions to swell amylopectin, thus preventing crystalline structures to form.
  • the framework polymer may be ether dissolved in mother solution or separated already from mother solution, but in a highly-swelled and highly-distributed condition.
  • a polymer framework is formed before phase separation begins. This framework polymer is newly formed from the mother solution and dissolved in the mother solution at the beginning.
  • phase separation starts, the framework polymer is first separated from the mother mixture and divides the system into many equal sized small regions, like many cages. Each of the small regions only allows forming one droplet in it. Since the framework polymer is uniformly distributed and all regions are identical, the final droplets formed are highly uniform in size.
  • a key to achieve such structure is the solubility of the framework polymer. Since selecting liquid crystals is mainly dependent on their optical and physical properties and selecting polymer including framework polymer is mainly depended their chemical reactivity, it is always difficult to meet both chemical requirements and physical requirements, including optical requirements, and achieve a good solubility.
  • the structure of benzophenones provides a great help, because it contains a ketone group, a hydroxyl phenolic group and a benzene ring. It is well-known that the ketone group has powerful solubility for many kinds of chemicals. In the present disclosure, ketone is used not only as a UV absorber, but also a solubility promoter. Furthermore, special designed benzophenons derivative may be directly used as a liquid crystal, therefore, this concentration of use may reach to a high level in comparison with normal use of UV absorbers.
  • FIG. 4 shows a comparison in electric-optical curves among LCMD films made by different technologies. Normalized transmittance is shown for different values of AC driving voltage applied to an LCMD film.
  • Curve 1 shows values of the electric-optical (E-O) relationship for a film made by NCAP technology.
  • Curve 2 shows values of the E-0 relationship for a film made by PDLC technology.
  • Curve 3 shows values of the E-0 relationship for a film made by NPD- LCD technology and including a dissolved framework polymer in the mixture used to form the LCMD material.
  • the dissolved framework polymer may be formed from monomers selected from those discussed above.
  • the new system of NPD-LCD utilizes "a dissolved framework polymer" to achieve highly identical sizes of microdroplets.
  • the film made by NPD-LCD technology was fully turned on at a voltage of less than 10 V AC, whereas the films made by prior techniques required voltages in the 50 to 60 volt range to reach maximum transmittance. This large reduction in voltage required to switch the liquid crystal in microdroplets means that power requirements for LCMD devices can be greatly reduced by using the materials and methods taught herein. .
  • the uniform polymer matrix has considerable solubility in the liquid crystal, acting as a plasticizer.
  • the liquid crystal phase or microdroplets also contain some of dissolved polymer as an impurity.
  • Such situation reduces the operational temperature range of NCAP film and PDLC film, which is usually within a range of 0 °C to 50 °C. Since the center regions of polymer matrix are formed containing framework polymer, which has a very high degree of polymerization in NPD-LCD film, these regions have a very low solubility to liquid crystal as a plasticizer.
  • Liquid phase or microdroplet is much purer than uniform polymer matrix in NCAP or PDLC matrixes, and results a much wider operational temperature range, such as from -30 °C to °80 C.
  • Purer liquid crystal phase also enlarges birefringence between two different orientations of liquid crystals and results a higher scattering or opacity.
  • UV absorber having reactive functional group may be used in a LCMD formula.
  • Such compounds, such as compound B series and compound C series, containing both UV absorbing group and reactive group to polymer matrix will remain in polymer matrix and have its protection effect.
  • X is a reactive functional group depending on the type of polymer matrix used. It may contain 1 to 10 carbons.
  • Rl may be an alkyl group.
  • UV absorber may be also put into plastic film 110 (FIG. 1).
  • Polyester UV protected film is commercially available, such as Mitsubishi film, Hostaphan 4333UV and 7333UV.
  • LCMD has been used for over a quarter of a century.
  • Most LCMD film 110 are made of polyester film or PET (polyethylene terephthalate).
  • PET polyethylene terephthalate
  • polycarbonate film should be better for UV resistance and weathering.

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

Abstract

Un dispositif d'affichage de microgouttelettes de cristaux liquides (AMCL) comprend une matrice polymère et des gouttelettes de matériau à cristaux liquides dispersées dans le polymère, la matrice polymère ou le cristal liquide comprenant un absorbeur UV. Le matériau AMCL peut être formé par séparation de phase avec un polymère de structure dissoute.
PCT/US2016/041058 2016-07-06 2016-07-06 Affichage de microgouttelettes de cristaux liquides basse tension et stable aux uv WO2018009174A1 (fr)

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CA3019756A CA3019756C (fr) 2016-07-06 2016-07-06 Affichage de microgouttelettes de cristaux liquides basse tension et stable aux uv
PCT/US2016/041058 WO2018009174A1 (fr) 2016-07-06 2016-07-06 Affichage de microgouttelettes de cristaux liquides basse tension et stable aux uv

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113667495A (zh) * 2021-08-13 2021-11-19 Oppo广东移动通信有限公司 用于电子设备壳体的组合物、聚合物分散液晶、聚合物分散液晶薄膜及其制备方法
EP4045970A4 (fr) * 2020-08-24 2023-11-08 Scienstry, Inc. Panneau commutable stable aux ir et stable aux uv et procédés de fabrication et d'utilisation

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US6362303B1 (en) * 2000-05-19 2002-03-26 Pleotint, L.L.C. Thermoscattering materials and devices
TW200621951A (en) * 2004-12-30 2006-07-01 Ind Tech Res Inst Polymer dispersed liquid crystal composition with improved photo-stability and the device thereof
US20150275090A1 (en) * 2014-03-22 2015-10-01 Jiansheng Wang UV Stable and Low-Voltage Liquid Crystal Microdroplet Display

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6362303B1 (en) * 2000-05-19 2002-03-26 Pleotint, L.L.C. Thermoscattering materials and devices
TW200621951A (en) * 2004-12-30 2006-07-01 Ind Tech Res Inst Polymer dispersed liquid crystal composition with improved photo-stability and the device thereof
US20150275090A1 (en) * 2014-03-22 2015-10-01 Jiansheng Wang UV Stable and Low-Voltage Liquid Crystal Microdroplet Display

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4045970A4 (fr) * 2020-08-24 2023-11-08 Scienstry, Inc. Panneau commutable stable aux ir et stable aux uv et procédés de fabrication et d'utilisation
CN113667495A (zh) * 2021-08-13 2021-11-19 Oppo广东移动通信有限公司 用于电子设备壳体的组合物、聚合物分散液晶、聚合物分散液晶薄膜及其制备方法

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