CN113655653A - Liquid crystal dimming device and preparation method and application thereof - Google Patents
Liquid crystal dimming device and preparation method and application thereof Download PDFInfo
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- CN113655653A CN113655653A CN202110864297.6A CN202110864297A CN113655653A CN 113655653 A CN113655653 A CN 113655653A CN 202110864297 A CN202110864297 A CN 202110864297A CN 113655653 A CN113655653 A CN 113655653A
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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
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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
- G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
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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
- G02F1/13347—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals working in reverse mode, i.e. clear in the off-state and scattering in the on-state
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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
- G02F1/137—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
- G02F1/13718—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 a change of the texture state of a cholesteric liquid crystal
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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
- G02F1/137—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
- G02F1/13775—Polymer-stabilized liquid crystal layers
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Abstract
The invention discloses a liquid crystal dimming device and a preparation method and application thereof, wherein the liquid crystal dimming device comprises at least two light-transmitting conductive substrates which are oppositely arranged, a polymer stable cholesteric liquid crystal layer is arranged between every two adjacent light-transmitting conductive substrates, and the polymer stable cholesteric liquid crystal layer comprises electrolyte, a polymer network and cholesteric liquid crystals dispersed in the polymer network; the electrolyte contains organic cations, and the polymer network can capture the organic cations in the electrolyte. The liquid crystal dimming device can simultaneously realize privacy protection and temperature regulation functions.
Description
Technical Field
The invention belongs to the technical field of light adjusting devices, and particularly relates to a liquid crystal light adjusting device and a preparation method and application thereof.
Background
With the development of science and technology, people pay more and more attention to resource conservation and development of environment-friendly materials while pursuing better material life. In daily life, more than 50% of energy is used for regulating indoor temperature and illumination, and thus, development of more environmentally friendly smart windows is particularly important in the field of construction. The development of smart windows has mainly focused on privacy protection or temperature regulation to meet the requirements of different conditions of consumers.
Most of the existing intelligent windows can only meet one requirement, but cannot simultaneously meet privacy protection and temperature regulation, for example, an infrared reflection intelligent window based on Polymer Stabilized Cholesteric Liquid Crystal (PSCLC) can effectively regulate incidence and reflection of infrared light through voltage control, and is the most effective means for realizing temperature regulation; the intelligent dimming window based on the Polymer Stabilized Liquid Crystal (PSLC) can enable liquid crystal molecules to rotate by applying voltage, reduce transmittance and enable a device to be blurred, and therefore the effect of privacy protection is achieved.
However, there is an increasing desire to satisfy both privacy protection and temperature regulation. Therefore, the development of a novel liquid crystal dimming device for protecting privacy and adjusting temperature is significant.
Statements in this background are not admitted to be prior art to the present disclosure.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides a liquid crystal dimming device which can have the functions of privacy protection and temperature regulation.
The invention also provides a preparation method of the liquid crystal dimming device.
The invention also provides an application of the liquid crystal dimming device.
According to one aspect of the invention, a liquid crystal dimming device is provided, which comprises at least two transparent conductive substrates arranged oppositely, wherein a parallel guide layer is arranged on one side opposite to the two adjacent transparent conductive substrates, a polymer stabilized cholesteric liquid crystal layer is arranged between the parallel guide layers, and the polymer stabilized cholesteric liquid crystal layer comprises an electrolyte, a polymer network and cholesteric liquid crystals dispersed in the polymer network; the electrolyte contains organic cations, and the polymer network can capture the organic cations in the electrolyte.
According to a preferred embodiment of the present invention, at least the following advantages are provided: the liquid crystal dimming device can simultaneously realize privacy protection and temperature regulation functions, liquid crystal molecules are arranged in parallel under the action of the parallel guide layer when voltage is not applied, at the moment, the reflection bandwidth is small, most infrared rays can penetrate through the liquid crystal dimming device, so that heat is generated, and the liquid crystal dimming device is in a non-heat insulation state; when a direct current voltage is connected, the polymer network captures cations in the liquid crystal mixture, and the cations move to the cathode under the action of the electric field, so that the polymer network near the cathode is compressed, and the polymer network near the anode is stretched, thereby forming a polymer stable cholesteric liquid crystal system with a certain pitch gradient. At the moment, the reflection bandwidth is widened, and more infrared rays can be reflected back to the atmosphere, so that the purpose of heat insulation is achieved; when the direct current is removed and the high-frequency low-voltage alternating current is applied, the cholesteric liquid crystals are disorderly arranged and are in a fuzzy state under the action of the electric field force, so that the effect of privacy protection can be realized; after the voltage is removed, the cholesteric liquid crystal molecules can again return to the original homeotropic alignment due to the presence of the polymer network.
In some preferred embodiments of the present invention, the number of polymer stabilized cholesteric liquid crystal layers between two adjacent light-transmitting conductive substrates is 1. The device with the single functional layer is not easy to have the adverse effects of failure and the like caused by vertical diffusion of liquid crystal which is easy to occur in a double-layer or multi-layer dimming device, and shows better stability.
In some embodiments of the invention, the electrolyte is a cationic surfactant; preferably, the cationic surfactant is selected from Cetyl Trimethyl Ammonium Bromide (CTAB), stearyl trimethylAmmonium bromide, cetylpyridinium chloride, tetradecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecyltrimethylammonium bromide (DTAB) or 1-tetradecyl-3 methylimidazolium bromide (C)18H35N2Br) is added. Other organic cation-containing electrolytes, or other cationic surfactants, may also be used.
In some embodiments of the invention, the polymer network is formed by the action of a crosslinkable liquid crystalline monomer and a photoinitiator. The electrolyte containing organic cations can drive the network to move towards the negative electrode under the condition of electrification, so that the polymer network is deformed.
In some preferred embodiments of the present invention, the crosslinkable liquid crystalline monomer is selected from acrylates with double bonds; more preferably, the crosslinkable liquid crystalline monomer is selected from at least one of RM82 or RM 257. The ester group groups on the polymer network capture impurity cations in the liquid crystal mixture, and under the action of an electric field, the cations move to the cathode, so that the polymer network near the cathode is compressed, and the polymer network near the anode is stretched, thereby forming a polymer stable cholesteric liquid crystal system with a certain pitch gradient.
In some preferred embodiments of the present invention, the photoinitiator is selected from compounds capable of initiating polymerization of unsaturated monomers under uv irradiation.
In some preferred embodiments of the present invention, the photoinitiator is selected from at least one of Irgacure-651, Irgacure-819, Irgacure-369, or Irgacure-184.
In some embodiments of the invention, the cholesteric liquid crystal is a helical structure formed from a dual frequency liquid crystal material and a chiral dopant. The dual-frequency liquid crystal material refers to a liquid crystal material in which the positive and negative of dielectric anisotropy (Delta epsilon) change with the change of alternating voltage frequency
In some embodiments of the present invention, the dual-frequency liquid crystal material exhibits negative dielectric constant (-. DELTA. epsilon.) when no electricity is applied at room temperature, and exhibits positive dielectric constant (+. DELTA. epsilon.) when a cross-linking voltage of a certain frequency is applied.
In some preferred embodiments of the present invention, the dual-frequency liquid crystal material is selected from the group consisting of light arrowhead species in commercial liquid crystal DP002-16 or HEF 951800-100.
In some preferred embodiments of the present invention, the chiral dopant is a levorotatory or dextrorotatory liquid crystal small molecule, preferably at least one selected from CB-15, S1011, R1011, S811 or R811.
In some embodiments of the invention, the polymer stabilized cholesteric liquid crystal layer further comprises a dichroic dye; preferably, the dichroic dye is selected from at least one of RL008, RL013, RL014 or RL 002. The dichroic dye has different absorption coefficients for light in the parallel or vertical light polarization directions, so that the device displays different colors when the polarized light passes through the dichroic dye in parallel or vertical, the defect that the reflection peak of the PSCLC device cannot display colors in an infrared band is overcome, the device has the characteristic of rich colors, and various requirements of people in daily life can be better met; when the device is under high voltage and high frequency, the liquid crystal molecules and the dichroic dye are vertically distributed with the substrate along with the increase of voltage, so that the device is in a transparent colorless state.
In some preferred embodiments of the present invention, the raw material for preparing the polymer stabilized cholesteric liquid crystal layer comprises a liquid crystal mixture and an electrolyte, wherein the liquid crystal mixture comprises 80-90 parts by mass of a dual-frequency liquid crystal material, 1-10 parts by mass of a crosslinkable liquid crystal monomer, 3-7 parts by mass of a chiral dopant, 1-5 parts by mass of a photoinitiator, and 0.1-0.5 part by mass of a dichroic dye, and the electrolyte is added in an amount of (1-5) x 10 per g of the liquid crystal mixture-6mol。
In some preferred embodiments of the present invention, the parallel-guiding layer is selected from one of a Polyimide (PI) layer or a polyvinyl alcohol (PVA) layer. Other materials commonly used for the parallel-guiding layer are also possible.
In some preferred embodiments of the present invention, the liquid crystal dimming device further comprises a driving component; the drive assembly comprises a power supply assembly, and the light-transmitting conductive substrate is electrically connected with the power supply assembly; preferably, the power supply assembly comprises a power supply, a switch and a wire; the power supply is electrically connected with the switch through a lead; more preferably, the power source is selected from at least one of a direct current and an alternating current power source. Two adjacent light-transmitting conductive substrates are respectively electrically connected with two poles of a power supply so as to control the voltage of the liquid crystal dimming device.
According to another aspect of the present invention, a method for manufacturing the above liquid crystal dimming device is provided, including the following steps:
and taking the light-transmitting conductive substrates, enabling the two adjacent light-transmitting conductive substrates to be oppositely arranged, arranging parallel guide layers on the opposite sides of the two oppositely arranged light-transmitting conductive substrates, filling preparation raw materials of the polymer stable cholesteric liquid crystal layer between the parallel guide layers, and solidifying the preparation raw materials to form the polymer stable cholesteric liquid crystal layer.
The preparation method according to a preferred embodiment of the present invention has at least the following advantageous effects: the preparation method of the scheme of the invention has the advantages of simple operation, good reproducibility and good industrial application prospect.
In some preferred embodiments of the invention, the filling uses capillary forces.
According to still another aspect of the present invention, a liquid crystal dimming device is provided, which includes the above liquid crystal dimming device and a power supply component electrically connected to the liquid crystal dimming device.
In some preferred embodiments of the invention, the power supply assembly comprises a power supply, a switch, and a wire; the power supply is electrically connected with the switch through a lead; more preferably, the power source is selected from at least one of a direct current and an alternating current power source. Two adjacent light-transmitting conductive substrates are respectively electrically connected with two poles of a power supply so as to control the voltage of the liquid crystal dimming device.
An intelligent dimming device comprises the liquid crystal dimming device.
In some preferred embodiments of the present invention, the smart dimming device is a smart window. The liquid crystal light-adjusting device can be prepared into an intelligent light-adjusting device such as a controllable adjusting window or a vehicle-mounted device.
An adjusting method of a liquid crystal dimming device comprises the following steps: the light transmission amount and/or transparency of the liquid crystal dimming device is controlled by adjusting the voltage of the power supply assembly.
In some preferred embodiments of the invention, the voltage of the regulated power supply component is direct current; preferably about 60V dc. The direct current is introduced to widen, so that the dimming component can be in a transparent and colored state.
In some preferred embodiments of the invention, the voltage of the power supply component is regulated to be alternating current with high frequency and low voltage; preferably, the high frequency and low voltage is 1kHz, and the voltage is 0-60V (60V is not included). The voltage is controlled within the range, so that the dimming component becomes fuzzy and colored, and is better protected.
In some preferred embodiments of the invention, the voltage of the power supply component is regulated to be alternating current with high frequency and high voltage; preferably, the high frequency and high voltage is 1kHz and the voltage is 60-100V. The voltage is controlled in the range, so that the dimming component becomes transparent and colorless, and the temperature is controlled better.
The application according to a preferred embodiment of the invention has at least the following advantageous effects: the light modulation device provided by the scheme of the invention has the advantages of simple structure, low cost, multiple functions and good application prospect. This dimming device can realize privacy protection and temperature regulation simultaneously, makes devices such as infrared reflection intelligent window have diversified printing opacity state, simultaneously, still energy-concerving and environment-protective, all has good application prospect in multiple scenes such as on-vehicle glass, building field, can satisfy people daily life's various demands.
Drawings
The invention is further described with reference to the following figures and examples, in which:
fig. 1 is a schematic structural diagram of an intelligent window in embodiment 3 of the present invention;
fig. 2 is a schematic structural diagram of a liquid crystal dimming device at a voltage of 0V in embodiment 3 of the present invention;
fig. 3 is a schematic structural diagram of a liquid crystal dimming device according to embodiment 3 of the present invention under a voltage of 60V;
fig. 4 is a schematic structural diagram of a liquid crystal dimming device in embodiment 3 of the present invention under high frequency and low voltage;
fig. 5 is a schematic structural diagram of a liquid crystal dimming device in embodiment 3 of the present invention under high frequency and high voltage;
FIG. 6 is a graph of wavelength versus light transmittance for conventional PSCLC at various voltages;
fig. 7 is a graph of wavelength-transmittance curves of the liquid crystal dimming device in example 3 of the present invention under different voltages.
Reference numerals: 11. a first light-transmitting conductive substrate body; 12. a first parallel-guiding layer; 21. a second light-transmitting conductive substrate body; 22. a second parallel-guiding layer; 3. a spacer; 4. a polymer stabilized cholesteric liquid crystal layer; 5. a liquid crystal mixture; 6. an electrolyte; 7. a dichroic dye; 8. a power supply assembly.
Detailed Description
The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention. The test methods used in the examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are commercially available reagents and materials unless otherwise specified.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Example 1
The embodiment prepares a liquid crystal dimming device, which includes a first light-transmitting conductive substrate and a second light-transmitting conductive substrate that are oppositely disposed, where the first light-transmitting conductive substrate includes a first light-transmitting conductive substrate body 11 and a first parallel guide layer 12 that are sequentially stacked, and the second light-transmitting conductive substrate includes a second light-transmitting conductive substrate body 21 and a second parallel guide layer 22 that are sequentially stacked. A spacer for controlling the thickness of a liquid crystal box is arranged between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate, the spacer is composed of silicon spheres and ultraviolet curing glue, the mass ratio of the silicon spheres to the ultraviolet curing glue is 1:99, and a polymer stable cholesteric liquid crystal layer prepared from a (1-tetradecyl-3 methylimidazolium bromide) liquid crystal mixture (80 wt% of dual-frequency liquid crystal DP002-016, 10 wt% of cross-linkable liquid crystal monomer RM257, 7 wt% of chiral dopant CB-15, 2.5 wt% of photoinitiator Irgacure-819 and 0.5 wt% of dichroic dye RL014) added with electrolyte is filled between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate through capillary force.
Example 2
The embodiment prepares a liquid crystal dimming device, which includes a first light-transmitting conductive substrate and a second light-transmitting conductive substrate that are oppositely disposed, where the first light-transmitting conductive substrate includes a first light-transmitting conductive substrate body 11 and a first parallel guide layer 12 that are sequentially stacked, and the second light-transmitting conductive substrate includes a second light-transmitting conductive substrate body 21 and a second parallel guide layer 22 that are sequentially stacked. The spacer 3 for controlling the thickness of the liquid crystal box is arranged between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate, the spacer 3 is composed of silicon spheres and ultraviolet curing glue, the mass ratio of the silicon spheres to the ultraviolet curing glue is 1:99, and a polymer stable cholesteric liquid crystal layer 4 prepared from a liquid crystal mixture 5(89.9 wt% of dual-frequency liquid crystal DP002-016, 5 wt% of cross-linkable liquid crystal monomer RM82, 4 wt% of chiral dopant S1011, 1 wt% of photoinitiator Irgacure-651 and 0.1 wt% of dichroic dye RL 0027) added with electrolyte 6 is filled between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate through capillary force.
The specific process is as follows:
s1, preparation of a liquid crystal box: the method comprises the steps of taking a first transparent conductive substrate body (ITO glass) and a second transparent conductive substrate body (ITO glass) which are clean, carrying out ultraviolet ozone treatment, carrying out spin coating on a polyvinyl alcohol solution, heating on a 60 ℃ hot stage for 1 hour, and cooling to room temperature to form a first parallel guide layer and a second parallel guide layer respectively, wherein the thickness of the parallel guide layers is generally 40-60 nm, and is about 50nm in the embodiment. And rubbing and orienting to obtain a first light-transmitting conductive substrate and a second light-transmitting conductive substrate which are attached with parallel alignment layers. The liquid crystal cell was fabricated by bonding with an ultraviolet curing adhesive contained in a spacer of 30 μm thickness.
S2, curing: respectively weighing 89.9 wt% of double-frequency liquid crystal HEF951800-100, 5 wt% of crosslinkable liquid crystal monomer RM82, 4 wt% of chiral dopant S1011, 1 wt% of photoinitiator Irgacure-651 and 0.1 wt% of dichroic dye under yellow light, mixing, and adding 1 x 10 per g of liquid crystal mixture-6mol CTAB, in hot stage at 50r/s, 6Stirring at 0 deg.C for 5min, and mixing to obtain liquid crystal mixture;
(2) under 60 ℃ hot stage, the liquid crystal mixture is filled into the liquid crystal box through capillary action, and a polymer stable cholesteric liquid crystal layer is formed under the action of chiral dopants. After 5 minutes of stabilization, the hot stage was closed, allowed to cool naturally to room temperature, and the device was placed at 32mw/cm2Curing for 3 minutes under the ultraviolet light to prepare the polymer stabilized cholesteric liquid crystal.
Wherein the crosslinkable liquid crystal monomer RM82 has a structural formula as follows:
the structural formula of the chiral dopant S1011 is:
the structural formula of the photoinitiator Irgacure-651 is as follows:
the structural formula of the dichroic dye RL002 is as follows:
example 3
In this embodiment, a (infrared reflection) smart window is prepared, and the specific process is as follows: taking the liquid crystal dimming device prepared in the embodiment 2 (comprising a first light-transmitting conductive substrate and a second light-transmitting conductive substrate which are oppositely arranged, wherein the first light-transmitting conductive substrate comprises a first light-transmitting conductive substrate body 11 and a first parallel guide layer 12 which are sequentially stacked, the second light-transmitting conductive substrate comprises a second light-transmitting conductive substrate body 21 and a second parallel guide layer which are sequentially stacked, a spacer 3 for controlling the thickness of a liquid crystal box is arranged between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate, the spacer 3 is composed of a silicon ball and ultraviolet curing glue, the mass ratio of the silicon ball to the ultraviolet curing glue is 1:99, and a polymer-stabilized cholesteric liquid crystal mixture 5(89.9 wt% of dual-frequency liquid crystal DP 002-002, 5 wt% of cross-linkable liquid crystal monomer 35RM 25, 4 wt% of chiral dopant S1011, 1 wt% of photoinitiator Irgacure-651 and 0.1 wt% of dichroic dye RL 7) added with electrolyte 6 is filled between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate through capillary force And the phase liquid crystal layer 4) to connect the first light-transmitting conductive substrate and the second light-transmitting conductive substrate with two electrodes of the power supply assembly 8, respectively, so as to obtain the intelligent window shown in fig. 1. Fig. 2 shows a schematic diagram of the liquid crystal dimming device when no voltage is applied. As can be seen from fig. 2, when the access voltage is 0V, the liquid crystal molecules are arranged in parallel, and at this time, the smart window can only reflect a small portion of the incoming infrared light, and has no influence on other bands, and is in a transparent colored non-heat-insulating state.
Fig. 3 shows a schematic diagram of a liquid crystal dimmer device when a dc voltage of 60V is applied. As can be seen from fig. 3, when the access voltage is 60V, the liquid crystal polymer network is compressed and stretched under the driving of the ion movement, and the cholesteric liquid crystal forms a pitch gradient, so that the reflection bandwidth is widened, at this time, the intelligent window can reflect most of infrared rays, and at this time, the intelligent window is in a transparent colored heat insulation state.
Fig. 4 shows a schematic diagram of a liquid crystal dimmer device when an ac voltage of 45V, 1kHz is applied. It can be seen from fig. 4 that when ac voltage of 45V and 1kHz is applied, the dual-frequency liquid crystal is dielectrically positive, and under the action of electric field force, the liquid crystal molecules rotate to form a focal conic state, which has a scattering effect on incident light, and a reflection effect is weaker, so that the smart window is in a fuzzy and colored state.
FIG. 5 shows a schematic diagram of a liquid crystal dimmer device when an AC voltage of 70V and 1kHz is applied. As can be seen from fig. 5, when an ac voltage of 70V and 1kHz is applied, the dual-frequency liquid crystal is dielectrically positive, and under the action of an electric field force, the liquid crystal molecules further rotate and are aligned perpendicular to the substrate, and since the absorption coefficient of the dichroic dye molecules is low, the smart window is in a transparent colorless state.
The measured light transmittances of the conventional infrared reflective smart window (PSCLC without electrolyte) and the PSCLC in example 3 at different wavelengths under the same conditions are shown in FIGS. 6-7. It can be seen from the figure that the addition of electrolytes such as CTAB has a better broadening effect.
In the above examples, the mechanism of action of the electrolytes such as CTAB is: when the number of the cations captured by the polymer network is larger, the positive electricity of the polymer network is stronger, the deformation of the network is larger under the action of an external voltage, the higher the compression or stretching degree of the thread pitch of the cholesteric phase is, and the thread pitch gradient is increased, so that the larger reflection bandwidth can be generated, and the effect of reflecting more infrared light is achieved. The electrolytes such as CTAB and the like mainly play a role in providing cations, and meanwhile, in a polymer stable cholesteric liquid crystal system, in the ultraviolet curing process, a certain amount of cations can be generated after the photoinitiator decomposes free radicals and organic matters, and the phenomenon of polymer network deformation can also be realized, but the effect is limited, so that some cations are needed to achieve a better broadening effect.
In summary, compared with the conventional infrared reflection intelligent window, the liquid crystal dimming device provided by the embodiment of the invention has multiple advantages of simple structure, low cost, multiple functions and the like. The adjusting window provided by the embodiment of the invention can be enabled to have four states of transparent colored non-heat insulation, transparent colored heat insulation, fuzzy colored non-heat insulation and transparent colorless non-heat insulation through voltage control, so that double effects of privacy protection and temperature adjustment are realized simultaneously, the infrared reflection intelligent window has diversified light transmission states, can meet various requirements of people in daily life, is diverse in application, is energy-saving and environment-friendly, and has a good application prospect in the fields of vehicle-mounted glass, buildings and the like.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.
Claims (10)
1. A liquid crystal light modulating device, characterized by: the liquid crystal display comprises at least two light-transmitting conductive substrates which are oppositely arranged, wherein parallel guide layers are arranged on the opposite sides of the two adjacent light-transmitting conductive substrates, a polymer stable cholesteric liquid crystal layer is arranged between the parallel guide layers, and the polymer stable cholesteric liquid crystal layer comprises electrolyte, a polymer network and cholesteric liquid crystal dispersed in the polymer network; the electrolyte contains organic cations, and the polymer network can capture the organic cations in the electrolyte.
2. The liquid crystal dimming device of claim 1, wherein: the electrolyte is a cationic surfactant; preferably, the cationic surfactant is selected from at least one of cetyltrimethylammonium bromide, octadecyltrimethylammonium bromide, cetylpyridinium chloride, tetradecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecyltrimethylammonium bromide or 1-tetradecyl-3 methylimidazolium bromide salt.
3. The liquid crystal dimming device of claim 1, wherein: the polymer network is formed by the action of a crosslinkable liquid crystal monomer and a photoinitiator; preferably, the crosslinkable liquid crystalline monomer is selected from acrylates with double bonds; more preferably, the crosslinkable liquid crystalline monomer is selected from at least one of RM82 or RM 257; preferably, the photoinitiator is selected from compounds capable of initiating polymerization of unsaturated monomers under uv irradiation; more preferably, the photoinitiator is selected from at least one of Irgacure-651, Irgacure-819, Irgacure-369 or Irgacure-184.
4. The liquid crystal dimming device of claim 1, wherein: the cholesteric liquid crystal is a spiral structure formed by a double-frequency liquid crystal material and a chiral dopant; preferably, the chiral dopant is a levorotatory or dextrorotatory liquid crystal small molecule, preferably at least one selected from CB-15, S1011, R1011, S811, or R811.
5. The liquid crystal dimming device of claim 1, wherein: what is needed isThe polymer stable cholesteric liquid crystal layer also contains a dichroic dye; preferably, the dichroic dye is selected from at least one of RL008, RL013, RL014 or RL 002; preferably, the preparation raw materials of the polymer stabilized cholesteric liquid crystal layer comprise a liquid crystal mixture and an electrolyte, the liquid crystal mixture comprises 80-90 parts by mass of a dual-frequency liquid crystal material, 1-10 parts by mass of a crosslinkable liquid crystal monomer, 3-7 parts by mass of a chiral dopant, 1-5 parts by mass of a photoinitiator and 0.1-0.5 part by mass of a dichroic dye, and the addition amount of the electrolyte is (1-5) x 10 per g of the liquid crystal mixture-6mol。
6. The liquid crystal dimming device of claim 1, wherein: the parallel orientation layer is selected from one of a polyimide layer or a polyvinyl alcohol layer.
7. A method for manufacturing a liquid crystal dimming device according to any one of claims 1 to 6, wherein: the method comprises the following steps:
and (2) arranging two light-transmitting conductive substrates oppositely, arranging a parallel guide layer on one side opposite to each light-transmitting conductive substrate, filling a preparation raw material of a polymer stable cholesteric liquid crystal layer between the parallel guide layers, and solidifying the preparation raw material to form the polymer stable cholesteric liquid crystal layer.
8. A liquid crystal dimming device is characterized in that: the liquid crystal dimming device comprises the liquid crystal dimming device according to any one of claims 1 to 6 and a power supply assembly electrically connected to the liquid crystal dimming device.
9. An intelligent dimming device, its characterized in that: the smart dimming device comprises the liquid crystal dimming device as claimed in claim 8.
10. A method of adjusting a liquid crystal dimming device according to claim 8, wherein: the method comprises the following steps: the light transmission amount and/or transparency of the liquid crystal dimming device is controlled by adjusting the voltage of the power supply assembly.
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