CN116243525A - Optical attenuation sheet based on liquid crystal mixture and preparation method thereof - Google Patents

Optical attenuation sheet based on liquid crystal mixture and preparation method thereof Download PDF

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CN116243525A
CN116243525A CN202211726670.2A CN202211726670A CN116243525A CN 116243525 A CN116243525 A CN 116243525A CN 202211726670 A CN202211726670 A CN 202211726670A CN 116243525 A CN116243525 A CN 116243525A
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liquid crystal
optical attenuation
dyes
attenuation sheet
crystal mixture
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CN116243525B (en
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李国强
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Shanghai Zhijingshi Optical Electromechanical Technology Co ltd
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    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • G02F1/137Devices 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
    • G02F1/13731Devices 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 field-induced phase transition
    • G02F1/13737Devices 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 field-induced phase transition in liquid crystals doped with a pleochroic dye
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    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00Liquid crystal materials
    • C09K19/52Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00Liquid crystal materials
    • C09K19/52Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • C09K19/60Pleochroic dyes
    • C09K19/601Azoic
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00Liquid crystal materials
    • C09K19/52Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • C09K19/60Pleochroic dyes
    • C09K19/603Anthroquinonic

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Abstract

The invention provides an optical attenuation sheet based on a liquid crystal mixture and a preparation method thereof, and the optical attenuation sheet comprises at least two transparent substrates, at least one liquid crystal box and an electro-optic material, wherein the liquid crystal box is arranged between two adjacent transparent substrates, the liquid crystal box is formed by integrating two transparent conductive films through viscose, the two transparent conductive films are respectively positioned on the inner surfaces of the two adjacent transparent substrates, the electro-optic material is arranged in the liquid crystal box, the electro-optic material is formed by mixing the liquid crystal material, a chiral material and a doping material with light absorption characteristic, and the two transparent conductive films of the liquid crystal box are connected with external voltage. The invention provides an optical attenuation sheet based on a liquid crystal mixture, which has simple structure and manufacture, does not need a liquid crystal alignment layer, and can realize the continuous attenuation of 2.56 multiplied by 10 of the maximum amplitude in the prior art 10 Or higher, and is independent of the polarization state of the light, the voltage used is very low<25V, low cost, compact device and small volume.

Description

Optical attenuation sheet based on liquid crystal mixture and preparation method thereof
Technical Field
The invention relates to the technical field of optical elements, in particular to an optical attenuation sheet based on a liquid crystal mixture and a preparation method thereof.
Background
An optical attenuator is a basic optical element that modulates the amplitude of light and finds application in any system where it is desirable to control the intensity of light. The attenuation of light is mainly achieved in the following ways: the absorption characteristics of a metal film, a dielectric film, a semiconductor film or a material with a certain thickness on light with different wavelengths are utilized to change the intensity of transmitted light. The attenuation of transmitted light is realized by using the surface reflection and reflection increasing film. The intensity of the transmitted light is reduced by the polarizer. The photochromic material is used, namely silver halide or organic color-changing molecules are added into glass or plastic, and the material has different absorption to visible light under strong light, normal light and weak light, so that the transmittance of the lens is changed. Electrochromic materials are utilized. When a voltage is applied to the electrochromic conductive polymer, the transmittance thereof varies with the variation of the voltage. In addition, some materials produce nonlinear absorption effects under strong laser irradiation, and the transmitted light intensity changes, but this phenomenon is not generally used as an optical attenuation sheet.
In practical applications, optical attenuation methods based on the first three effects are most used. The attenuation coefficient of the conventional optical attenuation sheet is fixed, e.g. 10 -1 ,10 -2 ,10 -3 ,10 -4 And so on. Multiple discrete damping effects can be achieved with a multi-plate combination, but continuously adjustable dynamic damping cannot be achieved. In daily life, various sunglasses are commonly used as daily necessities based on optical attenuation elements. Most sunglasses are based on multilayer optical interference films or polarizers to attenuate the intensity of transmitted light. According to the 2020 national standard (GB 39552.1), sunglasses are divided into five types according to visible light transmittance, wherein the visible light transmittance ratios of 0 type lens, 1 type lens, 2 type lens, 3 type lens and 4 type lens are respectively>80%, 43% -80%, 18% -43%, 8% -18%, 3% -8%. In different application scenes, sunglasses with different transmittance are required to be worn. Photochromic lenses are also commonly used in sunglasses, where the maximum transmittance isThe ratio to the minimum transmittance is typically around 4 and the response is slow, typically on the order of a few minutes. The contrast ratio of electrochromic lenses is typically around 10 and the response time is about 2 seconds.
Modern intelligent, energy-saving buildings and automobiles need to effectively control the light energy and indoor temperature entering the room, reduce the use of air conditioners, and simultaneously enjoy outdoor beauty in the room. To achieve this goal, it is desirable to have a smart window that is automatically responsive to ambient light, has a high transmittance contrast, has a low operating voltage, and is always transparent.
The existing optical attenuation element lacks a technology capable of realizing continuous adjustable transmittance, large contrast and quick response. Although continuously adjustable transmittance can be achieved by using two cascaded polarizers, the loss of light is large at the maximum transmittance state, and it is necessary to mechanically rotate one polarizer, which is not applicable in many cases. There have been proposed nematic liquid crystal lenses based on polarizing plates or electro-optical attenuation elements using other liquid crystal materials, but some techniques have not high contrast, have not high transmittance in an on state, and some techniques require a relatively large voltage to be applied.
Chinese patent CN112433403a discloses a light modulation device, which can improve transmittance by compounding a liquid crystal compound, a chiral compound, and a dichroic dye into a liquid crystal layer; however, its maximum contrast is only around 7; and it is not capable of achieving continuous adjustability of transmittance in the visible light range (400 to 700 nm) and the near infrared light range (700 to 800 nm);
disclosure of Invention
The application aims to provide an optical attenuation sheet based on a liquid crystal mixture, which has a simple structure, can realize continuous attenuation of large-range amplitude, is irrelevant to the polarization state of light, and has the advantages of low voltage, high response speed (100 milliseconds or faster) and low cost.
In order to achieve the above purpose, the present invention provides the following technical solutions:
the application discloses an optical attenuation sheet based on a liquid crystal mixture, which comprises at least two transparent substrates, at least one liquid crystal box and an electro-optic material, wherein the liquid crystal box is arranged between two adjacent transparent substrates, the liquid crystal box is formed by integrating two transparent conductive films through viscose, the two transparent conductive films are respectively positioned on the inner surfaces of the two adjacent transparent substrates, the electro-optic material is arranged in the liquid crystal box, and the electro-optic material is formed by mixing a liquid crystal material, a chiral material and a doped absorption material; the doped absorbing material is formed by mixing one or more dyes, wherein the dye is anthraquinone dye, azo dye or one of combined dyes of anthraquinone dye and azo dye; the up-down fluctuation of the doped absorption material in the wavelength range of 450-650 nanometers is less than or equal to 15% of the average value; the two transparent conductive films of the liquid crystal box are connected with external voltage, and the transmittance of the optical attenuation sheet is continuously adjustable along with the magnitude of the external voltage in the wavelength range of 400-800 nanometers.
Preferably, the doped absorbing material is formed by mixing three dyes, the half-peak width of absorption of the three dyes is more than 100nm, and the peak wavelengths of absorption of the three dyes are respectively 450+/-10 nm, 530+/-10 nm and 620+/-10 nm.
Preferably, the three dyes are Yellow AG1, red AR1, blue AB3 or Yellow AG1, redAR1, blue AB2 or Yellow AG1, orange AO1, blue AB3 or disperse yellow+disperse Red 1, respectively.
Preferably, the mass ratio of the liquid crystal material, the chiral material and the doped absorption material in the electro-optic material is ((1) (0.01-0.12)) (0.01-0.10).
Preferably, particles for controlling the thickness of the liquid crystal box are arranged in the adhesive, and the thickness of the liquid crystal box is 3-50 microns.
Preferably, the transparent base material has a thickness of 0.25 to 0.5 mm.
Preferably, the liquid crystal material is composed of four components as follows
Figure BDA0004030318740000041
The four components are mixed according to the proportion of 51%, 25%, 16% and 8% respectively;
the molecular formula of the chiral material is as follows:
Figure BDA0004030318740000042
the doped absorbing material is a bicolor dye.
Preferably, the number of the transparent substrates is 3, and the number of the liquid crystal cells is 2.
Preferably, the number of the transparent substrates is 4, and the number of the liquid crystal cells is 3.
Preferably, the number of the transparent substrates is 5, and the number of the liquid crystal cells is 4.
The invention also discloses a preparation method of the optical attenuation sheet based on the liquid crystal mixture, which comprises the following steps:
s1, selecting one or more dyes from anthraquinone dyes, azo dyes or combination dyes of the anthraquinone dyes and the azo dyes as doped absorption materials, so that the absorption spectrum amplitude of the doped absorption materials in the wavelength range of 450-650 nanometers is less than or equal to 15 percent;
s2, mixing a liquid crystal material, a chiral material and a doped absorption material, and stirring by using a stirring instrument to obtain a liquid crystal mixture material;
s3, raising the temperature of the heating table to be above a clearing point of the liquid crystal material, and placing the assembled transparent substrate (1) and the liquid crystal box on the heating table;
s4, injecting the liquid crystal mixture material from one end of the liquid crystal box until the liquid crystal mixture material fills the whole liquid crystal box, continuously placing the liquid crystal mixture material on a heating table, and reducing the temperature of the heating table to room temperature;
s5, connecting the two transparent conductive films (2) of the liquid crystal box with wires respectively to obtain the optical attenuation sheet.
Preferably, the temperature of the heating stage in the step S3 is lowered at a rate of 1 ℃/sec.
The invention has the beneficial effects that:
the invention provides an optical attenuation sheet based on a liquid crystal mixture, which has simple structure and manufacture and does not need liquid crystal molecular orientationA layer capable of realizing maximum range amplitude continuous attenuation 2.56×10 in the current field 10 Or higher (contrast up to 400 or more, two orders of magnitude higher than the technique of chinese patent CN112433403 a), and is independent of the polarization state of the light, the voltage used is low<25V, low cost, compact device and small volume.
The optical attenuation sheet of the invention has continuously adjustable transmittance, is applicable to the whole visible light spectrum (wavelength range 400-700 nm) and near infrared band (700-800 nm), and is also applicable to any narrow band spectrum (several nanometers, tens of nanometers, 100nm, etc.) in the spectrum.
The features and advantages of the present invention will be described in detail by way of example with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic structural view of an optical attenuator based on a liquid crystal mixture according to the present invention;
FIG. 2 is a schematic diagram of a second embodiment of the present invention;
FIG. 3 is a schematic view of a third embodiment of the present invention;
FIG. 4 is a schematic diagram of a fourth embodiment of the present invention;
FIG. 5 is a plot of voltage versus transmittance for a single liquid crystal cell according to experiment one of the present invention;
FIG. 6 is a plot of voltage versus transmittance for a single liquid crystal cell of experiment two of the present invention;
FIG. 7 is a plot of voltage versus transmittance for a single liquid crystal cell of experiment three of the present invention;
FIG. 8 is a component structural formula of the liquid gold material of the present invention;
FIG. 9 is a component structural formula of a chiral material of the present invention;
wherein: 1-transparent substrate, 2-transparent conductive film, 3-electro-optic material and 4-adhesive.
Detailed Description
The present invention will be further described in detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention.
Embodiment one:
referring to fig. 1, an embodiment of the present invention provides an optical attenuation sheet based on a liquid crystal mixture, which includes two transparent substrates 1, a liquid crystal box and an electro-optic material 3, wherein the liquid crystal box is disposed between two adjacent transparent substrates 1, the liquid crystal box is formed by integrating two transparent conductive films 2 through an adhesive 4, the two transparent conductive films 2 are respectively disposed on the inner surfaces of the two adjacent transparent substrates 1, the electro-optic material is disposed in the liquid crystal box, and the electro-optic material is formed by mixing a liquid crystal material, a chiral material and a doping material having an absorption characteristic to light; the doped absorbing material is formed by mixing three dyes, wherein the dye is anthraquinone dye, azo dye or one of combined dyes of the anthraquinone dye and the azo dye; the up-down fluctuation of the doped absorption material in the wavelength range of 450-650 nanometers is less than or equal to 15% of the average value; the half-peak width of the absorption of the three dyes exceeds 100nm, and the wavelengths of the absorption peaks of the three dyes are respectively 450+/-10 nm, 530+/-10 nm and 620+/-10 nm; the two transparent conductive films 2 of the liquid crystal box are connected with external voltage; the transmittance of the optical attenuation sheet is continuously adjustable along with the magnitude of external voltage in a visible light wide spectrum (wavelength range 400-700 nanometers) and a near infrared band (700-800 nanometers), and any narrow-band spectrum (several nanometers, tens of nanometers, 100 nanometers and the like) in the spectrum is also continuously adjustable along with the magnitude of external voltage. The mass ratio of the liquid crystal material, the chiral material and the doped absorbing material in the electro-optic material is ((1) (0.01-0.12)), (0.01-0.10) -the adhesive 4 is internally provided with particles for controlling the thickness of a liquid crystal box, the thickness of the liquid crystal box is 3-50 microns, the thickness of the transparent substrate material is 0.25-0.5 mm, and the ratio of the maximum transmittance to the minimum transmittance of the optical attenuation sheet can reach 400.
Embodiment two:
referring to fig. 2, the distinguishing technical features of the present embodiment and the first embodiment are: the number of transparent substrates 1 is 3, the number of liquid crystal cells is 2,different external voltages can be respectively applied to the two liquid crystal boxes to respectively adjust the transmittance of the two liquid crystal boxes, so that the ratio of the maximum transmittance to the minimum transmittance of the optical attenuation sheet can reach 1.6X10 5
Embodiment III:
referring to fig. 3, the distinguishing technical features of the present embodiment and the first embodiment are: the number of the transparent substrates 1 is 4, the number of the liquid crystal boxes is 3, different external voltages can be respectively applied to the 3 liquid crystal boxes to respectively adjust the transmittance of the 3 liquid crystal boxes, so that the ratio of the maximum transmittance to the minimum transmittance of the optical attenuation sheet can reach 6.4x10 7
Embodiment four:
referring to fig. 4, the distinguishing technical features of the present embodiment and the first embodiment are: the number of the transparent substrates 1 is 5, the number of the liquid crystal boxes is 4, different external voltages can be respectively applied to the 4 liquid crystal boxes to respectively adjust the transmittance of the 4 liquid crystal boxes, so that the ratio of the maximum transmittance to the minimum transmittance of the optical attenuation sheet can reach 2.56 multiplied by 10 10
The materials of the first to fourth embodiments may be selected as follows:
for liquid crystal materials, one possible choice is E7, manufactured by EMD Chemicals (Merck) and made up of the components shown in FIG. 8 mixed in proportions of 51%, 25%, 16% and 8%, respectively, other nematic liquid crystals being possible to achieve the object of the invention;
regarding chiral materials, one possible choice is R811 or R5011 manufactured by EMD Chemicals (Merck) as an example, the molecular structure of R811 is shown in FIG. 9, and other chiral materials are possible to achieve the object of the present invention;
the doped absorbing material is formed by mixing one or more dyes, wherein the dye is one of anthraquinone dye, azo dye or a combination dye of the anthraquinone dye and the azo dye; the absorption spectrum amplitude of the doped absorption material in the wavelength range of 450-650 nanometers is less than or equal to 15 percent.
Experiment one:
the mass ratio of the liquid crystal material to the chiral material to the doped absorption material in the electro-optic material of the optical attenuation sheet in the experiment is 1:0.01:0.01, wherein the doped absorption material is formed by mixing three dyes, namely Yellow AG1, red AR1 and Blue AB3; the half-peak width of absorption of the three dyes is more than 100nm, and the wavelengths of absorption peaks of the three dyes are respectively 450nm, 521nm and 620nm; the dye mixture after superposition has relatively uniform absorption spectrum (up-down fluctuation is less than or equal to 15% of average value) in the wavelength range of 450-650 nm.
The thickness of the liquid crystal box is 20 micrometers, when an external voltage is applied to the liquid crystal box, a relation graph of the voltage and the transmittance of the single liquid crystal box is shown as 5, and the maximum transmittance and the minimum transmittance of the single liquid crystal box are 466 and 1.9 respectively in the range of 0-20 volts of the external voltage, and the contrast ratio is higher than 200;
experiment II:
the mass ratio of the liquid crystal material to the chiral material to the doped absorption material in the electro-optic material of the optical attenuation sheet in the experiment is 1.1:0.12:0.10, and the mass ratio of the chiral material to the doped absorption material is 1:0.01:0.01, wherein the doped absorption material is formed by mixing three dyes, namely Yellow AG1, red AR1 and Blue AB2; the half-peak width of absorption of the three dyes is more than 100nm, and the wavelengths of absorption peaks of the three dyes are respectively 450nm, 521nm and 610nm; the absorption spectrum of the dye mixture after superposition is relatively uniform (the fluctuation is less than or equal to 15% of the average value) in the wavelength range of 450-650 nanometers;
the thickness of the liquid crystal box is 20 micrometers, when an external voltage is applied to the liquid crystal box, a relation graph of the voltage and the transmittance of the single liquid crystal box is shown as 6, and the maximum transmittance and the minimum transmittance of the single liquid crystal box are 523 and 1.6 respectively in the range of 0-20 volts of the external voltage, and the contrast ratio is higher than 300;
experiment II:
the mass ratio of the liquid crystal material to the chiral material to the doped absorption material in the electro-optic material of the optical attenuation sheet in the experiment is 1:0.06:0.05, wherein the doped absorption material is formed by mixing three dyes, namely Yellow AG1, orange AO1 and Blue AB3; the half-peak width of absorption of the three dyes is more than 100nm, and the wavelengths of absorption peaks of the three dyes are respectively 450nm, 520nm and 620nm; the absorption spectrum of the dye mixture after superposition is relatively uniform (the fluctuation is less than or equal to 15% of the average value) in the wavelength range of 450-650 nanometers;
the thickness of the liquid crystal cell was 20 micrometers, and when an applied voltage was applied to the liquid crystal cell, the relationship between the voltage and the transmittance of the individual liquid crystal cell was measured and shown in fig. 7, and it was found that the maximum transmittance and the minimum transmittance of the individual liquid crystal cell were 692 and 1.7, respectively, and the contrast ratio was higher than 400 in the range of 0-20 volts applied voltage.
The manufacturing process of the optical attenuation sheet comprises the following steps: one or more dyes selected from anthraquinone dye, azo dye or combination dye of anthraquinone dye and azo dye are used as doped absorption materials, so that the up-down fluctuation of the absorption spectrum of the doped absorption materials with the wavelength range of 450-650 nanometers is less than or equal to 15% of the average value;
mixing a liquid crystal material, a chiral material and a doped absorption material according to a certain mass ratio, and stirring by using a stirring instrument; raising the temperature of the heating table above the clear point of the liquid crystal material, placing the assembled liquid crystal box on the heating table, injecting a liquid crystal mixture material from one end of the liquid crystal box by using a thin glass rod after 10 minutes, continuously placing the device on the heating table after the mixture fills the whole liquid crystal box, and cooling the heating table to room temperature at a speed of about 1 ℃/sec; the two conductive film layers of the device are respectively connected with a wire, so that the device can be used; the transmittance of the optical attenuator is controlled by the applied electric field. The applied voltage is 1 KHz alternating current square wave voltage, a signal generator generates alternating current square wave with certain amplitude, an amplifier amplifies the amplitude, and an output signal is applied to an optical attenuation sheet. By adjusting the amplitude of the signal amplifier, a voltage signal with a greater amplitude adjustment can be obtained at the output of the amplifier.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, or alternatives falling within the spirit and principles of the invention.

Claims (10)

1. An optical attenuation sheet based on a liquid crystal mixture, characterized in that: the liquid crystal display device comprises at least two transparent substrates (1), at least one liquid crystal box and electro-optic materials (3), wherein the liquid crystal box is arranged between two adjacent transparent substrates (1), the liquid crystal box is formed by integrating two transparent conductive films (2) through viscose glue (4), the two transparent conductive films (2) are respectively positioned on the inner surfaces of the two adjacent transparent substrates (1), the electro-optic materials are arranged in the liquid crystal box, and the electro-optic materials are formed by mixing liquid crystal materials, chiral materials and doped absorption materials; the doped absorbing material is formed by mixing one or more dyes, wherein the dye is anthraquinone dye, azo dye or one of combined dyes of anthraquinone dye and azo dye; the up-down fluctuation of the absorption spectrum of the doped absorption material in the wavelength range of 450-650 nanometers is less than or equal to 15% of the average value; the two transparent conductive films (2) of the liquid crystal box are connected with external voltage; the transmittance of the optical attenuation sheet is continuously adjustable along with the magnitude of external voltage in the wavelength range of 400-800 nanometers.
2. An optical attenuation sheet based on a liquid crystal mixture as set forth in claim 1, wherein: the doped absorption material is formed by mixing three dyes, the absorption half-peak widths of the three dyes are all more than 100nm, and the absorption peak wavelengths of the three dyes are respectively positioned at 450+/-10 nm, 530+/-10 nm and 620+/-10 nm.
3. An optical attenuation sheet based on a liquid crystal mixture as set forth in claim 2, wherein: the three dyes are Yellow AG1, red AR1, blue AB3 or Yellow AG1, red AB 1, blue AB2 or Yellow AG1, orange AO1, blue AB3 or disperse yellow+disperse Red 1 respectively.
4. An optical attenuation sheet based on a liquid crystal mixture as set forth in claim 1, wherein: the mass ratio of the liquid crystal material, the chiral material and the doped absorption material in the electro-optic material is ((1):
(0.01-0.12)):(0.01-0.10))。
5. an optical attenuation sheet based on a liquid crystal mixture as set forth in claim 1, wherein: the viscose (4) is internally provided with particles for controlling the thickness of the liquid crystal box, and the thickness of the liquid crystal box is 3-50 microns.
6. An optical attenuation sheet based on a liquid crystal mixture as set forth in claim 1, wherein: the thickness of the transparent substrate material is 0.25-0.5 mm.
7. An optical attenuation sheet based on a liquid crystal mixture as set forth in claim 1, wherein: the liquid crystal material consists of the following four components
Figure FDA0004030318730000021
The four components are mixed according to the proportion of 51%, 25%, 16% and 8% respectively;
the molecular formula of the chiral material is as follows:
Figure FDA0004030318730000022
8. an optical attenuation sheet based on a liquid crystal mixture as set forth in claim 1, wherein: the number of the transparent substrates (1) is 3, and the number of the liquid crystal boxes is 2.
9. The preparation method of the optical attenuation sheet based on the liquid crystal mixture is characterized by comprising the following steps:
s1, selecting one or more dyes from anthraquinone dyes, azo dyes or combination dyes of the anthraquinone dyes and the azo dyes as doped absorption materials, so that the up-down fluctuation of the absorption spectrum of the doped absorption materials in the wavelength range of 450-650 nanometers is less than or equal to 15% of the average value;
s2, mixing a liquid crystal material, a chiral material and a doped absorption material, and stirring by using a stirring instrument to obtain a liquid crystal mixture material;
s3, raising the temperature of the heating table to be above a clearing point of the liquid crystal material, and placing the assembled transparent substrate (1) and the liquid crystal box on the heating table;
s4, injecting the liquid crystal mixture material from one end of the liquid crystal box until the liquid crystal mixture material fills the whole liquid crystal box, continuously placing the liquid crystal mixture material on a heating table, and reducing the temperature of the heating table to room temperature;
s5, connecting the two transparent conductive films (2) of the liquid crystal box with wires respectively to obtain the optical attenuation sheet.
10. The method for manufacturing an optical attenuator based on a liquid crystal mixture according to claim 1, wherein: the temperature of the heating table in the step S3 is reduced at a rate of 1 ℃/sec.
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Citations (8)

* Cited by examiner, † Cited by third party
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