阅读说明：本技术 一种反射器及其制备方法与应用 (Reflector as well as preparation method and application thereof ) 是由 赵威 韦群美 吕朋荣 迪克·杨·波尔 周国富 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种反射器及其制备方法与应用,所述反射器依次包括有透光基板一、调光层和透光基板二,调光层包括液晶聚合物层和小分子液晶层,液晶聚合物层和小分子液晶层由液晶混合物通过光聚合诱导分层形成,液晶聚合物层和小分子液晶层手性旋向相反。本发明公开的反射器的反射率高,且反射率及反射光旋向可调,制备所需材料易得,制备过程简单,只需简单曝光就能制备、无需洗出或填充,适用于工业化生产。(The invention discloses a reflector and a preparation method and application thereof, wherein the reflector sequentially comprises a light-transmitting substrate I, a dimming layer and a light-transmitting substrate II, the dimming layer comprises a liquid crystal polymer layer and a small molecule liquid crystal layer, the liquid crystal polymer layer and the small molecule liquid crystal layer are formed by layering a liquid crystal mixture through photopolymerization induction, and the chiral rotation directions of the liquid crystal polymer layer and the small molecule liquid crystal layer are opposite. The reflector disclosed by the invention has the advantages of high reflectivity, adjustable reflectivity and adjustable rotating direction of reflected light, easily obtained materials required for preparation, simple preparation process, preparation by simple exposure without washing or filling, and suitability for industrial production.)

1. The reflector is characterized by sequentially comprising a first light-transmitting substrate, a dimming layer and a second light-transmitting substrate, wherein the dimming layer comprises a liquid crystal polymer layer and a small molecular liquid crystal layer, the liquid crystal polymer layer and the small molecular liquid crystal layer are formed by layering a liquid crystal mixture through photopolymerization induction, and the chiral rotation directions of the liquid crystal polymer layer and the small molecular liquid crystal layer are opposite.

2. A reflector according to claim 1, wherein said liquid crystal polymer layer is a cholesteric liquid crystal polymer network and said small molecule liquid crystal layer is cholesteric liquid crystal; preferably, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, a non-polymerizable liquid crystal small molecule, a photoinitiator, a polymerizable chiral dopant and a non-polymerizable chiral dopant, wherein the chirality of the polymerizable chiral dopant and the chirality of the non-polymerizable chiral dopant are opposite; preferably, the raw materials of the liquid crystal polymer layer comprise a polymerizable liquid crystal monomer, a polymerizable chiral dopant, a photoinitiator and non-polymerizable liquid crystal small molecules; preferably, the raw materials of the small molecule liquid crystal layer comprise non-polymerizable liquid crystal small molecules and non-polymerizable chiral dopants; preferably, the ratio of the mass parts of the polymerizable liquid crystal monomer and the photoinitiator is (30-45) to (0.1-1); preferably, the mass part ratio of the polymerizable liquid crystal monomer to the non-polymerizable liquid crystal micromolecule is (30-45) to (45-60); preferably, the ratio of the polymerizable liquid crystal monomer to the polymerizable chiral dopant in parts by mass is (30-45): (1-9); preferably, the ratio of the mass parts of the non-polymerizable liquid crystal small molecules to the non-polymerizable chiral dopant is (45-60): (1-9).

3. A reflector according to claim 2, wherein said non-polymerizable liquid crystal small molecules comprise positive liquid crystals; preferably, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, positive liquid crystal, a photoinitiator, a polymerizable chiral dopant and a non-polymerizable chiral dopant; preferably, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, positive liquid crystal, a photoinitiator, a right-handed polymerizable chiral dopant and a left-handed non-polymerizable chiral dopant; preferably, the liquid crystal polymer layer comprises a cholesteric liquid crystal polymer network, and is formed by a polymerizable liquid crystal monomer, a right-handed polymerizable chiral dopant, a photoinitiator and positive liquid crystal; preferably, the small molecule liquid crystal layer is a levorotatory cholesteric liquid crystal layer consisting of positive liquid crystal and a levorotatory non-polymerizable chiral dopant; preferably, the ratio of the mass parts of the polymerizable liquid crystal monomer, the positive liquid crystal, the photoinitiator, the polymerizable chiral dopant and the non-polymerizable chiral dopant is (30-45): (45-60): (0.1-1): (1-9).

4. A reflector according to claim 2, wherein said polymerizable liquid crystal monomer comprises an acrylate monomer; preferably, the polymerizable liquid crystal monomer comprises at least one of monofunctional acrylate or difunctional acrylate; preferably, the monofunctional acrylate comprises at least one of HCM-020, HCM-021, HCM-022, HCM-039, HCM-040, HCM-042, HCM-043, HCM-044, HCM-045, HCM-046, HCM-047, HCM-048, HCM-049, HCM-050, HCM-059, HCM-062, HCM-065, HCM-066, HCM-074, HCM-075, HCM-076, HCM-078, HCM-079, HCM-080, HCM-083, HCM-091, HCM-108, HCM-109, HCM-110, HCM-116, HCM-126 or HCM-127; preferably, the difunctional acrylate comprises at least one of HCM-002, HCM-008, HCM-006, HCM-009, HCM-026, HCM-028, HCM-053, HCM-072, HCM-087, or HCM-125.

5. A reflector according to claim 2, wherein said polymerizable chiral dopant of right-handed rotation comprises at least one of HCM-006 or RM 96; preferably, the non-polymerizable chiral dopant of the levorotary comprises at least one of S811, S1011, S5011 or S6N.

6. A reflector according to claim 2, wherein said photoinitiator comprises a uv photoinitiator; preferably, the photoinitiator comprises at least one of Irgacure-127, Irgacure-1173, Irgacure-184, Irgacure-819, Irgacure-651, Irgacure-369 or Irgacure-2959.

7. A reflector according to claim 3, wherein the positive liquid crystal comprises at least one of 5CB, E7 or HTW 138200-100.

8. A reflector according to claim 1, wherein a first parallel alignment layer is disposed on a side of the first transparent substrate facing the liquid crystal mixture, and a second parallel alignment layer is disposed on a side of the second transparent substrate facing the liquid crystal mixture; preferably, the dimming layer is located between the first parallel alignment layer and the second parallel alignment layer; preferably, the first light-transmitting substrate is a first light-transmitting conductive substrate, and the second light-transmitting substrate is a second light-transmitting conductive substrate; preferably, the reflector comprises a first light-transmitting conductive substrate, a first parallel alignment layer, a liquid crystal polymer layer, a small molecular liquid crystal layer, a second parallel alignment layer and a second light-transmitting conductive substrate which are sequentially stacked; preferably, the reflector further comprises a power supply assembly, and two poles of the power supply assembly are electrically connected with the first light-transmitting conductive substrate and the second light-transmitting conductive substrate respectively.

9. A method of making a reflector, comprising the steps of:

and (3) taking the first light-transmitting substrate and the second light-transmitting substrate, adding a liquid crystal mixture between the first light-transmitting substrate and the second light-transmitting substrate, and illuminating to form a liquid crystal polymer layer and a small molecular liquid crystal layer, namely a dimming layer.

10. Use of the reflector according to any one of claims 1 to 8 or prepared by the preparation method according to claim 9 in the fields of construction, furniture, liquid crystal display, laser emission or biosensing.

Technical Field

The invention relates to the technical field of liquid crystal materials, in particular to a reflector and a preparation method and application thereof.

Background

At present, liquid crystal reflective devices are widely used in displays, lasers, smart windows, biosensors, and the like. Most of the existing liquid crystal reflecting devices are based on selective reflection of cholesteric liquid crystals, and the left-handed circularly polarized light (L-CPL) or right-handed circularly polarized light (R-CPL) is reflected by the adjusting device through selecting the handedness of the added chiral dopant. However, the liquid crystal reflective device only occupies 50% of natural light, regardless of L-CPL or R-CPL, so that the reflectivity of the liquid crystal reflective device is only 50% at most, and the rest 50% of natural light is transmitted. Meanwhile, due to the fact that the processes of mismatching of refractive indexes of the polymer and the micromolecular liquid crystal and the like exist, scattering phenomena are caused, and the reflectivity of the liquid crystal reflector is greatly reduced.

When the two kinds of polarization of the circularly polarized light can be reflected by the liquid crystal reflecting device at the same time, the reflection limit of 50% is exceeded, which is called super reflection phenomenon. Nowadays, the method for preparing the super-reflective liquid crystal device comprises the following steps: (1) stacking a plurality of layers of liquid crystal polymer films with opposite rotation directions to obtain a super-reflecting device capable of reflecting left-handed circularly polarized light and right-handed circularly polarized light simultaneously; (2) the liquid crystal polymer layer is prepared, liquid components in the liquid crystal polymer layer are washed out, and finally liquid components with the rotation direction opposite to that of the liquid crystal polymer layer are filled to obtain the super-reflecting device. The preparation method of the super-reflecting device is complex in process and complex in operation.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides the reflector which has the characteristics of simple preparation process and simple and convenient operation.

The invention also provides a preparation method of the reflector.

The invention also provides the application of the reflector.

The invention provides a reflector, which sequentially comprises a first light-transmitting substrate, a dimming layer and a second light-transmitting substrate, wherein the dimming layer comprises a liquid crystal polymer layer and a small molecule liquid crystal layer, the liquid crystal polymer layer and the small molecule liquid crystal layer are formed by layering a liquid crystal mixture through photopolymerization induction, and the chiral rotation directions of the liquid crystal polymer layer and the small molecule liquid crystal layer are opposite.

The reflector provided by the embodiment of the invention has at least the following beneficial effects: the invention utilizes photopolymerization to induce the stratification effect to prepare and obtain the liquid crystal polymer layer and the micromolecular liquid crystal layer with opposite chiral handedness, thereby obtaining the super-reflecting device. The invention has the advantages of simple and easily obtained required materials, simple and feasible preparation process, short time consumption of the preparation process, convenient operation, high reflectivity (the reflectivity is higher than 90%) of the reflector, excellent performance, capability of ensuring good reflection effect and lasting effect, and can be applied to industrial production by using lower materials and simple and convenient preparation processes.

In addition, the reflector disclosed by the invention has the characteristics of high reflectivity and heating or electrifying adjustable rotation direction of reflected light (the dimming layer has temperature response and electric response), and the reflector specifically comprises the following components: because the chiral directions of the liquid crystal polymer layer and the small molecule liquid crystal layer are opposite, the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light at room temperature in an unpowered state, and the reflector has a super-reflection effect. The small molecular liquid crystal layer is regulated and controlled, the reflector is heated or an electric field is applied to the reflector, the small molecular liquid crystal layer is changed into an isotropic state by heating, the orientation of the small molecular liquid crystal layer is changed into a zoom cone state by electrifying, the liquid crystal polymer layer is hardly influenced, the reflector cannot reflect left-handed circularly polarized light (or right-handed circularly polarized light), the reflectivity of the reflector is less than 50%, and the super-reflection effect is avoided. When the temperature is reduced to room temperature or the electric field is removed, the small molecular liquid crystal layer returns to the initial state, the small molecular liquid crystal layer can reflect left-handed circularly polarized light (or right-handed circularly polarized light), the polymer layer reflects right-handed circularly polarized light (or left-handed circularly polarized light), the reflectivity of the reflector is larger than 90%, and the reflector achieves a super-reflection effect. Wherein, the reflection waveband of the reflector can be realized by adjusting the type or content of the chiral raw material in the liquid crystal mixture.

In some embodiments of the invention, the liquid crystalline polymer layer is a cholesteric liquid crystalline polymer network.

In some embodiments of the invention, the small molecule liquid crystal layer is a cholesteric liquid crystal.

In some embodiments of the present invention, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, a non-polymerizable liquid crystal small molecule, a photoinitiator, a polymerizable chiral dopant and a non-polymerizable chiral dopant, wherein the chirality of the polymerizable chiral dopant and the non-polymerizable chiral dopant is opposite.

Through the implementation mode, the super-reflection target can be achieved by only one-step illumination polymerization (ultraviolet exposure) to separate two cholesteric phase liquid crystals with opposite chirality, and cholesteric phase liquid crystals with different chirality are formed step by step without heating and applying an electric field in the preparation process. Specifically, the photopolymerization-induced delamination process may be: the illumination (which may be uv exposure) causes the polymerizable monomers (including polymerizable liquid crystal monomers, polymerizable chiral dopants) in the liquid crystal mixture to be initiated, at a faster rate, on the side closer to the light source (upper layer) such that the polymerizable monomers diffuse to the side closer to the light source, resulting in the formation of a liquid crystal polymer layer (right-handed or left-handed) on the side closer to the light source (upper layer). Meanwhile, since the polymerizable monomer (the right-handed or left-handed polymerizable chiral dopant) diffuses to the side (upper layer) near the light source so that the non-polymerizable chiral dopant (the left-handed or right-handed) is pushed to the side (lower layer) far from the light source, the content of the non-polymerizable chiral dopant (the left-handed or right-handed) at the side (lower layer) far from the light source is high, and thus a small molecule liquid crystal layer (the left-handed or right-handed) is formed at the side (lower layer) far from the light source.

Meanwhile, the reflector has reversible temperature response, and the transmitted light is regulated and controlled by a heating method, wherein the temperature response is based on the liquid crystal temperature range of the material. Because the main components of the small molecular liquid crystal layer are small molecular liquid crystal and non-polymerizable chiral dopant, when the temperature of the reflector is lower (such as 25 ℃), the liquid crystal of the small molecular liquid crystal layer is in an anisotropic liquid crystal phase and is arranged parallel to the transparent substrate, and at the moment, the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light simultaneously. When the temperature of the reflector is raised (such as to 50 ℃), which is higher than the clearing point temperature of the small molecular liquid crystal, the liquid crystal of the small molecular liquid crystal layer is converted into an isotropic liquid state from the original anisotropic liquid crystal phase, the clearing point temperature is raised due to the existence of the polymer network in the liquid crystal polymer layer, the molecules still maintain the cholesteric phase arrangement parallel to the light-transmitting substrate, and the reflector can only reflect right-handed circularly polarized light (or left-handed circularly polarized light). When the temperature of the reflector is reduced to a lower temperature (such as 25 ℃), the liquid crystal of the small molecular liquid crystal layer is converted from the original isotropic liquid state into an anisotropic liquid crystal state, and is converted back to an orientation parallel to the light-transmitting substrate, and the liquid crystal polymer layer still maintains the parallel orientation, so that the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light simultaneously.

In some preferred embodiments of the present invention, the raw materials of the liquid crystal polymer layer include a polymerizable liquid crystal monomer, a polymerizable chiral dopant, a photoinitiator, and a non-polymerizable liquid crystal small molecule.

In some preferred embodiments of the present invention, the raw material of the small molecule liquid crystal layer comprises a non-polymerizable liquid crystal small molecule and a non-polymerizable chiral dopant.

In some preferred embodiments of the present invention, the ratio of parts by mass of the polymerizable liquid crystalline monomer and the photoinitiator is (30-45) to (0.1-1).

In some preferred embodiments of the present invention, the ratio of the mass parts of the polymerizable liquid crystal monomer and the non-polymerizable liquid crystal small molecule is (30-45) to (45-60).

In some preferred embodiments of the present invention, the ratio of parts by mass of the polymerizable liquid crystalline monomer to the polymerizable chiral dopant is (30-45): (1-9).

In some preferred embodiments of the present invention, the ratio of the mass parts of the non-polymerizable liquid crystal small molecules to the non-polymerizable chiral dopant is (45-60): (1-9).

In some more preferred embodiments of the present invention, the ratio of parts by mass of the polymerizable liquid crystal monomer, the positive liquid crystal, the photoinitiator, the polymerizable chiral dopant and the non-polymerizable chiral dopant is (30-45): (45-60): (0.1-1): (1-9). The wave band of the reflection peak is adjusted by regulating the concentration of the chiral dopant. The height of one period of the cholesteric liquid crystal molecules in the helical form is called the pitch, and the direction of rotation of the pitch defines the chirality of the cholesteric liquid crystal. The pitch, the helical twist direction and the refractive index of the cholesteric phase together determine the optical properties of the cholesteric liquid crystal. The pitch of the cholesteric liquid crystal is related to the ability of the chiral dopant to induce a continuous uniform Helical Twist (HTP) of the nematic liquid crystal director, the concentration (c) of the chiral dopant, as follows:

P＝1/(HTP*c)

the periodic spiral structure of the cholesteric liquid crystal can generate Bragg reflection effect on light, so that the cholesteric liquid crystal has selective reflection of a specific waveband. The reflection wavelength (λ) depends on the pitch (P) of the cholesteric liquid crystal and the average refractive index (n) of the liquid crystal, which are related as follows:

λ＝n*P

when the concentration of the chiral dopant is simultaneously increased, the pitch P of the cholesteric liquid crystal decreases, with a consequent decrease in the reflection wavelength, and vice versa. In addition, the rotation direction of P determines that theoretically one layer of cholesteric liquid crystal can only reflect circularly polarized light with the same direction as the torsion direction, and the reflectivity is only 50 percent at most. Meanwhile, different kinds of chiral dopants have different Helical Twisting Power (HTP). When the HTP of the chiral dopant is larger, the reflection peak is shorter at the same content, whereas when the HTP of the chiral dopant is smaller, the reflection peak is longer at the same content. When the same chiral dopant is used and the content of the chiral dopant is increased, the reflection waveband is blue-shifted; conversely, if the content of the chiral dopant is decreased, the reflection band is red-shifted.

Therefore, the reflector has super reflectivity (> 50%) in a visible light waveband and an infrared waveband and excellent temperature response performance by adjusting the type of the chiral dopant and the concentration of the chiral dopant, and can be dynamically adjusted and controlled along with the temperature.

In some preferred embodiments of the present invention, the non-polymerizable liquid crystalline small molecules comprise a positive liquid crystal.

In some more preferred embodiments of the present invention, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, a positive liquid crystal, a photoinitiator, a polymerizable chiral dopant, and a non-polymerizable chiral dopant.

In some more preferred embodiments of the present invention, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, a positive liquid crystal, a photoinitiator, a right-handed polymerizable chiral dopant, and a left-handed non-polymerizable chiral dopant.

In some more preferred embodiments of the present invention, the raw materials of the liquid crystal polymer layer include a polymerizable liquid crystal monomer, a right-handed polymerizable chiral dopant, a photoinitiator, and a positive liquid crystal.

In some more preferred embodiments of the present invention, the liquid crystal polymer layer comprises a cholesteric liquid crystal polymer network, the liquid crystal polymer layer being formed from a polymerizable liquid crystal monomer, a right-handed polymerizable chiral dopant, a photoinitiator, and a positive liquid crystal.

With the above embodiment, the liquid crystal polymer layer has a right-handed polymer structure and can reflect right-handed circularly polarized light.

In some more preferred embodiments of the present invention, the raw material of the small molecule liquid crystal layer includes a positive liquid crystal and a non-polymerizable chiral dopant of a left-handed orientation.

In some more preferred embodiments of the present invention, the small molecule liquid crystal layer is a levorotatory cholesteric liquid crystal layer consisting of a positive liquid crystal and a levorotatory non-polymerizable chiral dopant.

In the above embodiment, the small molecule liquid crystal layer has a left-handed cholesteric liquid crystal structure, and can reflect left-handed circularly polarized light.

In some more preferred embodiments of the present invention, the liquid crystal polymer layer is a cholesteric liquid crystal polymer network formed of a polymerizable liquid crystal monomer, a right-handed polymerizable chiral dopant, a photoinitiator, and a positive liquid crystal, and the small molecule liquid crystal layer is a levorotatory cholesteric liquid crystal composed of a positive liquid crystal and a levorotatory non-polymerizable chiral dopant.

Through the embodiment, the right-handed polymerizable chiral dopant (which can be a right-handed chiral liquid crystal monomer), the polymerizable liquid crystal monomer and the left-handed non-polymerizable chiral dopant are mixed together, before the polymerization is performed under the illumination, because the helical twisting force of the right-handed polymerizable chiral dopant is larger, the right-handed polymerizable chiral dopant is dominant at the moment, the left-handed twisting force is covered due to racemization, the reflector can only reflect right-handed circularly polarized light, and the reflectivity is less than 50%. The illumination (which may be ultraviolet exposure) causes the polymerizable liquid crystal monomer to be initiated at a faster rate at the side near the light source (upper layer), so that the polymerizable monomer (including the polymerizable liquid crystal monomer and the right-handed polymerizable chiral dopant) diffuses to the side near the light source, resulting in the formation of a right-handed liquid crystal polymer layer at the side near the light source (upper layer). Meanwhile, since the polymerizable monomer diffuses to the side close to the light source (upper layer) so that the levorotatory non-polymerizable chiral dopant is pushed to the side far from the light source (lower layer), the content of the levorotatory non-polymerizable chiral dopant at the side far from the light source (lower layer) is high, and thus a levorotatory small molecule liquid crystal layer is formed at the side far from the light source (lower layer).

In some more preferred embodiments of the present invention, the ratio of parts by mass of the polymerizable liquid crystal monomer, the positive liquid crystal, the photoinitiator, the polymerizable chiral dopant and the non-polymerizable chiral dopant is (30-45): (45-60): (0.1-1): (1-9).

In some preferred embodiments of the present invention, the polymerizable liquid crystal monomer comprises an acrylate monomer.

In some more preferred embodiments of the present invention, the polymerizable liquid crystal monomer comprises at least one of a monofunctional acrylate or a difunctional acrylate.

It should be noted that "functional group" specifically refers to a carbon-carbon double bond, and the functional group is mainly used for photopolymerization, particularly ultraviolet light polymerization. The invention can ensure that the liquid crystal polymer layer and the small molecule liquid crystal layer can coexist and exist stably by adjusting the proportion of each component.

In some more preferred embodiments of the invention, the monofunctional acrylate comprises at least one of HCM-020, HCM-021, HCM-022, HCM-039, HCM-040, HCM-042, HCM-043, HCM-044, HCM-045, HCM-046, HCM-047, HCM-048, HCM-049, HCM-050, HCM-059, HCM-062, HCM-065, HCM-066, HCM-074, HCM-075, HCM-076, HCM-078, HCM-079, HCM-080, HCM-083, HCM-091, HCM-108, HCM-109, HCM-110, HCM-116, HCM-126 or HCM-127.

The reagent can be purchased from the market, and manufacturers comprise Jiangsu and Chengxi display science and technology GmbH and the like.

In some more preferred embodiments of the present invention, the difunctional acrylate comprises at least one of HCM-002, HCM-008, HCM-006, HCM-009, HCM-026, HCM-028, HCM-053, HCM-072, HCM-087, or HCM-125.

The reagent can be purchased from the market, and manufacturers comprise Jiangsu and Chengxi display science and technology GmbH and the like.

In some preferred embodiments of the present invention, the polymerizable chiral dopant of the right-handed configuration comprises at least one of HCM-006 or RM 96.

The reagent can be purchased from the market, and manufacturers comprise Jiangsu and Chengxi display science and technology GmbH and the like.

In some preferred embodiments of the invention, the non-polymerizable chiral dopant that is left-handed comprises at least one of S811, S1011, S5011 or S6N.

The above reagents are commercially available, and the manufacturers include Jiangsu Hecheng display technology, Inc., Beijing eight billion space-time liquid crystal technology, Inc.

In some preferred embodiments of the present invention, the photoinitiator comprises a uv photoinitiator.

In some more preferred embodiments of the present invention, the photoinitiator comprises at least one of Irgacure-127, Irgacure-1173, Irgacure-184, Irgacure-819, Irgacure-651, Irgacure-369, or Irgacure-2959.

The reagents are commercially available, and manufacturers include Schensz, Merck, and the like.

In some preferred embodiments of the present invention, the positive liquid crystal comprises at least one of 5CB, E7 or HTW 138200-100.

The above reagents are commercially available, and manufacturers include Jiangsu and Chengxi display technologies, Inc., Merck, etc.

In some embodiments of the present invention, the thickness of the dimming layer is 30 to 100 um.

In some embodiments of the present invention, the first light-transmissive substrate has a light transmittance ranging from 95% to 100%.

In some embodiments of the present invention, the second light-transmitting substrate has a light transmittance ranging from 95% to 100%.

In some embodiments of the present invention, a first parallel alignment layer is disposed on a side of the first transparent substrate facing the liquid crystal mixture, and a second parallel alignment layer is disposed on a side of the second transparent substrate facing the liquid crystal mixture.

With the above embodiment, the first parallel alignment layer and the second parallel alignment layer can have completely the same structure. The materials and the preparation process are consistent.

In some preferred embodiments of the present invention, a raw material of the first parallel alignment layer includes at least one of polyvinyl alcohol or polyimide.

In some preferred embodiments of the present invention, the raw material of the second parallel alignment layer includes at least one of polyvinyl alcohol or polyimide.

In some preferred embodiments of the present invention, the dimming layer is located between the first and second parallel alignment layers.

In some more preferred embodiments of the present invention, the first light-transmitting substrate, the first parallel alignment layer, the dimming layer, the second parallel alignment layer, and the second light-transmitting substrate are sequentially stacked.

In some more preferred embodiments of the present invention, the first transparent substrate, the first parallel alignment layer, the liquid crystal polymer layer, the small molecule liquid crystal layer, the second parallel alignment layer, and the second transparent substrate are sequentially stacked.

In some embodiments of the present invention, the first light-transmitting substrate is a first light-transmitting conductive substrate.

In some embodiments of the present invention, the second light-transmitting substrate is a second light-transmitting conductive substrate.

In some embodiments of the present invention, the first transparent substrate is a first transparent conductive substrate, and the second transparent substrate is a second transparent conductive substrate.

In some preferred embodiments of the present invention, the liquid crystal mixture comprises a polymerizable liquid crystal monomer, a positive liquid crystal, a photoinitiator, a polymerizable chiral dopant, and a non-polymerizable chiral dopant.

Through the embodiment, the reflector has reversible electrical response while having reversible circulating temperature response, has excellent performance, can be dynamically regulated and controlled along with temperature and an electric field, is easy to regulate and control, expands the application range of the reflector, and can be applied to the technical field of optics and display. In practical application, the content of the chiral dopant can be adjusted as required to obtain reflectors with different reflection wave bands, the reflectors have super-reflectivity (reflectivity higher than 90%), temperature response and electric response performance in visible light wave bands and infrared light wave bands, the reflectors can have reversible circulating temperature response and electric response, namely, the regulation and control of transmitted light are realized by a heating or power-up method, the equipment performance is improved, the reflectors can be applied to industrial production by using relatively cheap materials and simple and convenient preparation processes, and the application prospect is good.

The electric response principle of the reflector is based on the mechanism that positive liquid crystal molecules tend to align parallel to the direction of an electric field under the action of the electric field. The reflector is polymerized to form a liquid crystal polymer layer and a small molecule liquid crystal layer. Because the main components of the micromolecule liquid crystal layer are positive liquid crystal and non-polymerizable chiral dopant, when an access electric field U is equal to 0V, the liquid crystal of the micromolecule liquid crystal layer is arranged in parallel to the light-transmitting conductive substrate, the device is transparent, and the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light at the same time. When an electric field U ≠ 0V is applied (for example, U ═ 120V), the positive liquid crystal molecules are converted into focal conic state orientation from the original orientation parallel to the light-transmitting conductive substrate, while the liquid crystal molecules in the liquid crystal polymer layer still maintain the cholesteric phase arrangement parallel to the light-transmitting conductive substrate due to the existence of the polymer network, and the device can be kept in a fuzzy state, and at the moment, the reflector can only reflect right-handed circularly polarized light (or left-handed circularly polarized light). When the electric field U is removed to 0V, the positive liquid crystal molecules are switched back to the orientation aligned parallel to the light-transmissive conductive substrate by the orientation layer, while the liquid crystal polymer layer remains in the parallel orientation, and the device can reflect both left-handed and right-handed circularly polarized light.

Therefore, the reflector disclosed by the invention has the characteristics of high reflectivity and heating or electrifying adjustable rotating direction of reflected light, and specifically comprises the following steps: because the chiral directions of the liquid crystal polymer layer and the small molecule liquid crystal layer are opposite, the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light at room temperature in an unpowered state, and the reflector has a super-reflection effect. The small molecular liquid crystal layer is regulated and controlled, the reflector is heated or an electric field is applied to the reflector, the small molecular liquid crystal layer is changed into an isotropic state by heating, the orientation of the small molecular liquid crystal layer is changed into a zoom cone state by electrifying, the liquid crystal polymer layer is hardly influenced, the reflector cannot reflect left-handed circularly polarized light (or right-handed circularly polarized light), the reflectivity of the reflector is less than 50%, and the super-reflection effect is avoided. When the temperature is reduced to room temperature or the electric field is removed, the small molecular liquid crystal layer returns to the initial state, the small molecular liquid crystal layer can reflect left-handed circularly polarized light (or right-handed circularly polarized light), the polymer layer reflects right-handed circularly polarized light (or left-handed circularly polarized light), the reflectivity of the reflector is larger than 90%, and the reflector achieves a super-reflection effect. Wherein, the reflection waveband of the reflector can be realized by adjusting the type or content of the chiral raw material in the liquid crystal mixture.

In some preferred embodiments of the present invention, the first light-transmitting conductive substrate, the first parallel alignment layer, the dimming layer, the second parallel alignment layer, and the second light-transmitting conductive substrate are sequentially stacked.

In some more preferred embodiments of the present invention, the first light-transmitting conductive substrate, the first parallel alignment layer, the liquid crystal polymer layer, the small molecule liquid crystal layer, the second parallel alignment layer, and the second light-transmitting conductive substrate are sequentially stacked.

In some preferred embodiments of the present invention, the reflector further includes a power supply component, and two poles of the power supply component are electrically connected to the first light-transmitting conductive substrate and the second light-transmitting conductive substrate, respectively.

In some further preferred embodiments of the invention, the power supply assembly comprises an ac power supply having a voltage regulating device integrated thereon.

Through the embodiment, the voltage adjusting device is integrated on the alternating current power supply, and the power supply voltage can be directly adjusted. The two poles of the power supply assembly are electrically connected with the first light-transmitting conductive substrate and the second light-transmitting conductive substrate respectively, and voltage is applied between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate through the power supply assembly.

In a second aspect of the present invention, a method for manufacturing a reflector is provided, including the following steps:

and (3) taking the first light-transmitting substrate and the second light-transmitting substrate, adding a liquid crystal mixture between the first light-transmitting substrate and the second light-transmitting substrate, and illuminating to form a liquid crystal polymer layer and a small molecular liquid crystal layer, namely a dimming layer.

The preparation method of the reflector provided by the embodiment of the invention has at least the following beneficial effects: the preparation method utilizes the photopolymerization to induce the layering effect to prepare the liquid crystal polymer layer and the small molecule liquid crystal layer with opposite chiral rotation directions, thereby obtaining the super-reflecting device. The reflecting device belongs to an integrated device, the required materials are simple and easy to obtain, the preparation process is simple and easy to implement, the time consumption of the preparation process is short, the operation is convenient, the reflecting device can be prepared by simple exposure without washing or filling, and the reflecting device is suitable for industrial production and application. Meanwhile, the reflector has high reflectivity (the reflectivity is higher than 90%), excellent performance, good reflection effect and lasting effect, and can be applied to industrial production by using lower-cost materials and simple and convenient preparation processes. In some embodiments of the present invention, the first light-transmitting substrate and the second light-transmitting substrate are packaged into a liquid crystal cell, and a liquid crystal mixture is filled into the liquid crystal cell.

In some embodiments of the present invention, the method further includes step S0-1, preparing a first parallel alignment layer on the first transparent substrate and a second parallel alignment layer on the second transparent substrate by using parallel alignment layer materials, respectively.

In some preferred embodiments of the present invention, a raw material of the first parallel alignment layer includes at least one of polyvinyl alcohol or polyimide.

In some preferred embodiments of the present invention, the raw material of the second parallel alignment layer includes at least one of polyvinyl alcohol or polyimide.

In some more preferred embodiments of the present invention, a raw material solution of the first parallel alignment layer is spin-coated on the first light-transmitting substrate to obtain the first parallel alignment layer.

In some more preferred embodiments of the present invention, the mass fraction of the raw materials in the raw material solution of the first parallel alignment layer is 3 to 5%.

In some more preferred embodiments of the present invention, the raw material solution of the first parallel alignment layer is an aqueous solution of a raw material.

In some more preferred embodiments of the present invention, an aqueous solution of a raw material of the second parallel alignment layer is spin-coated on the second light-transmitting substrate to obtain the second parallel alignment layer.

In some more preferred embodiments of the present invention, the mass fraction of the raw materials in the raw material solution of the second parallel alignment layer is 3 to 5%.

In some more preferred embodiments of the present invention, the raw material solution of the second parallel alignment layer is an aqueous solution of a raw material.

In some preferred embodiments of the present invention, in step S0-1, an aqueous solution of polyvinyl alcohol is spin-coated on the surfaces of the first and second transparent substrates, respectively, and rubbing alignment is performed to obtain a first parallel alignment layer and a second parallel alignment layer.

In some preferred embodiments of the present invention, the method further includes step S0-2, where the first parallel alignment layer and the second parallel alignment layer are disposed opposite to each other, spacers are disposed on edges of the first transparent substrate where the first parallel alignment layer is disposed, the second transparent conductive substrate is disposed on the uv curable adhesive containing the spacers, and the first transparent substrate and the second transparent substrate are packaged into a liquid crystal cell.

In some more preferred embodiments of the present invention, a polymerizable liquid crystal monomer, a positive liquid crystal, a chiral dopant (including a polymerizable chiral dopant and a non-polymerizable chiral dopant) and a photoinitiator are mixed to obtain a liquid crystal mixture, and the liquid crystal mixture is filled into a liquid crystal cell and naturally cooled to room temperature.

In some further preferred embodiments of the present invention, the liquid crystal mixture is filled in an isotropic state into a liquid crystal cell having parallel alignment layers.

By the above embodiment, the liquid crystal mixture is filled into the liquid crystal cell having the parallel alignment layer in the isotropic state, so that the alignment effect of the liquid crystal molecules is better, the defects in the device are less, and the final reflectivity of the reflector is higher.

In some embodiments of the invention, the light source for illumination is an ultraviolet light source.

In some preferred embodiments of the present invention, the light intensity during the illumination is 0.5-120mW cm^-2。

In some more preferred embodiments of the present invention, the light intensity during the illumination is 0.5-25mW cm^-2。

In some preferred embodiments of the present invention, the light wavelength during illumination is 280-405 nm.

In some more preferred embodiments of the present invention, the light wavelength during illumination is 365 nm.

In some preferred embodiments of the present invention, the illumination time is 5 to 60 min.

In some more preferred embodiments of the present invention, the illumination time is 60 min.

In a third aspect of the invention, the use of the above reflector in the fields of construction, furniture, liquid crystal display, laser emission or biosensing is proposed.

In some embodiments of the invention, the use of the above reflector in a display, a laser, a smart window or a biosensor is proposed.

Drawings

The invention is further described with reference to the following figures and examples, in which:

FIG. 1 is a schematic view of the structure inside a liquid crystal cell of a reflector according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a reflector according to an embodiment of the present invention in a state where the reflector is not energized and the 120V AC current is applied;

FIG. 3 is a graph of the transmittance spectrum of a reflector in an embodiment of the invention in the absence of power and with 120V of alternating current applied;

FIG. 4 is a schematic structural diagram of a reflector in an embodiment of the present invention at room temperature of 25 deg.C and heated to 50 deg.C;

FIG. 5 is a graph of the transmission spectrum of a reflector in an embodiment of the invention at 25 deg.C room temperature and heated to 50 deg.C;

FIG. 6 is a graph showing the results of the chiral dopant content required for different reflection bands of a reflector according to an embodiment of the present invention;

fig. 7 is a transmittance spectrum diagram of reflectors of different reflected wave bands in the embodiment of the present invention.

Reference numerals: 11. a first light-transmitting conductive substrate; 21. a first parallel orientation layer; 31. a liquid crystal polymer layer; 41. a small molecule liquid crystal layer; 22. a second parallel alignment layer; 12. and a second light-transmitting conductive substrate.

Detailed Description

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, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present numbers, and the above, below, within, etc. are understood as including the present numbers. If one or two are described, the technical features are used for distinguishing, and the relative importance is indicated or implied, the number of the indicated technical features is implicitly indicated, or the precedence relationship of the indicated technical features is implicitly indicated.

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.

Details of the chemical reagents used in the examples of the present invention are as follows:

the chemical structural formula of polymerizable liquid crystal monomer HCM021 (available from Jiangsu and Chengshi technologies Co., Ltd.) is:

the chemical structure of polymerizable liquid crystal monomer HCM008 (available from Jiangsu and Chengshi technologies, Inc.) is:

the chemical structure of the polymerizable liquid crystal monomer HCM006 (available from Jiangsu and Chengshi technologies Co., Ltd.) is:

the chemical formula of the small molecular liquid crystal 5CB (purchased from Jiangsu and Chengshi technologies Co., Ltd.) is as follows:

the chemical structure of the unpolymerizable L-chiral dopant S1011 (available from Jiangsu and Chengshi technologies Co., Ltd.) is:

the photoinitiator Irgacure-651 (available from Merck, Germany) has the chemical formula:

example 1

A reflector, as shown in fig. 1, includes a first light-transmitting conductive substrate 11, a second light-transmitting conductive substrate 12, and a dimming layer, where the dimming layer includes a liquid crystal polymer layer 31 and a small molecule liquid crystal layer 41, which are prepared from a liquid crystal mixture by a photopolymerization-induced layering technique and have opposite chiral rotation directions, and thus, specifically, the reflector includes the first light-transmitting conductive substrate 11, the first parallel alignment layer 21, the liquid crystal polymer layer 31, the small molecule liquid crystal layer 41, the second parallel alignment layer 22, and the second light-transmitting conductive substrate 12, which are sequentially stacked. The liquid crystal mixture comprises a polymerizable liquid crystal monomer, positive liquid crystal, a photoinitiator, a right-handed polymerizable chiral dopant and a left-handed non-polymerizable chiral dopant. The liquid crystal polymer layer is of a right-handed polymer structure and specifically comprises a right-handed cholesteric liquid crystal polymer network, and the small molecular liquid crystal layer is a left-handed liquid crystal layer and specifically is a left-handed cholesteric liquid crystal.

The reflector further comprises a power supply assembly, and two poles of the power supply assembly are electrically connected with the first light-transmitting conductive substrate 11 and the second light-transmitting conductive substrate 12 respectively.

The power supply assembly comprises an alternating current power supply, a voltage regulating device is integrated on the alternating current power supply, and the voltage regulating device is integrated on the alternating current power supply and can directly regulate the power supply voltage. The two poles of the power supply assembly are electrically connected with the first light-transmitting conductive substrate and the second light-transmitting conductive substrate respectively, and voltage is applied between the first light-transmitting conductive substrate and the second light-transmitting conductive substrate through the power supply assembly.

The preparation method of the reflector comprises the following steps:

(1) the first light-transmitting conductive substrate and the second light-transmitting conductive substrate are oppositely arranged. And respectively spin-coating a polyvinyl alcohol aqueous solution (the mass fraction of polyvinyl alcohol is 5.0%) of the parallel orientation layer on the surfaces of the first light-transmitting conductive substrate and the second light-transmitting conductive substrate, and performing rubbing orientation to obtain a first parallel orientation layer and a second parallel orientation layer. And placing a spacer on the edge of the surface of the first transparent conductive substrate provided with the parallel alignment layer, placing a second transparent conductive substrate on the ultraviolet curing adhesive containing the spacer, and packaging the first transparent conductive substrate and the second transparent conductive substrate into a liquid crystal box.

(2) In a yellow environment (emission without uv may also be used)Other light sources of the line), 0.0300g of crosslinkable liquid crystal monomer HCM021, 0.0110g of crosslinkable liquid crystal monomer HCM008, 0.0047g of crosslinkable right-handed chiral liquid crystal monomer HCM006, 0.0019g of left-handed chiral dopant S1011, 0.0534g of 5CB and 0.0005g of photoinitiator Irgacure-651 are weighed and placed in a brown bottle, 2ml of dichloromethane is added to promote dissolution, the brown bottle is placed at 60 ℃ and stirred and heated for 5h to completely volatilize the solvent, and simultaneously the mixture is stirred uniformly at the rotating speed of 200r/S to convert the liquid crystal material mixture into an isotropic liquid crystal mixture and reduce the viscosity of the mixture. Then injecting the liquid crystal material mixture into a liquid crystal box at the temperature, standing and cooling to room temperature, wherein the strength of the liquid crystal material mixture is 1.5mW cm^-2And ultraviolet light with the wavelength of 365nm is cured for 60 minutes to obtain the cholesteric liquid crystal reflector with good orientation and super-reflection optical characteristics.

Example 2

A reflector which differs from example 1 in that it is produced by a process which comprises: a package frame was formed by UV-curable adhesive and a spacer of 50 μm, and the strength was 25 mW/cm^-2And packaging the liquid crystal box by using the ultraviolet light with the wavelength of 365 nm.

Example 3

A reflector which differs from example 1 in that it is produced by a process which comprises: filling the liquid crystal mixture into a liquid crystal box on a 60 ℃ hot bench through capillary force, preserving the heat for 30min to ensure that the liquid crystal can be well oriented, and then naturally cooling to room temperature; then at 0.5mW cm^-2And (5) curing for 1h under ultraviolet light to obtain the liquid crystal reflecting device.

Example 4

Reflectors I-III were prepared separately, differing from example 1 in the content of chiral dopant, as specified in Table 1 below:

TABLE 1 prepared reflectors with different content of reflector chiral dopants

It should be noted that:

1. the reflector IV is the reflector prepared in the example 1;

2. the mass percentages (wt.%) in table 1 refer to the mass percentage of each chiral dopant in the liquid crystal mixture.

Test examples

This test example tested the performance of the reflectors prepared in examples 1-4. Wherein:

the transmittance of the reflector prepared in example 1 was measured in the non-energized and 120V ac applied state, and the results are shown in fig. 3, under the following conditions: uv spectrophotometer test using PerkinElmer LAMBDA 950, unpowered state: the incident light is unpolarized light, the temperature is 25 ℃, and the voltage is 0V; and (3) electrifying state: the incident light is unpolarized light, the temperature is 25 ℃, and the voltage is 120V.

The transmittance of the reflector prepared in example 1 was measured at room temperature of 25 c and heated to 50 c, and the results are shown in fig. 5, under the following conditions: test using PerkinElmer LAMBDA 950 uv spectrophotometer, room temperature conditions: the incident light is unpolarized light, the temperature is 25 ℃, and the voltage is 0V; heating state: the incident light is unpolarized light, the temperature is 50 ℃, and the voltage is 0V.

The transmittance of the reflector prepared in example 1 and the transmittance of the reflector prepared in example 4 in different reflection wavelength bands were measured, and the measurement results are shown in fig. 7, where the test conditions are as follows: the test was carried out using a Perkinelmer LAMBDA 950 UV spectrophotometer, with unpolarized light incident at 25 ℃ and a voltage of 0V.

As shown in fig. 2 and 3, the electric response principle of the reflector is based on the mechanism that positive liquid crystal molecules tend to be aligned parallel to the direction of an electric field under the action of the electric field. The reflector is polymerized to form a liquid crystal polymer layer and a small molecule liquid crystal layer. Because the main components of the micromolecule liquid crystal layer are positive liquid crystal and a left-handed non-polymerizable chiral dopant, when an access electric field U is equal to 0V, the liquid crystal of the micromolecule liquid crystal layer is arranged in parallel to the light-transmitting conductive substrate, the device is transparent, and the device can reflect left-handed circularly polarized light and right-handed circularly polarized light at the same time. When an electric field U is switched in to 120V, positive liquid crystal molecules are converted into focal conic state orientation from the original orientation parallel to the light-transmitting conductive substrate, the liquid crystal molecules in the liquid crystal polymer layer are still arranged parallel to the light-transmitting conductive substrate due to the existence of the polymer network, the device can be kept in a fuzzy state, and at the moment, the reflector can only reflect right-handed circularly polarized light. When the electric field U is removed to 0V, the positive liquid crystal molecules are switched back to the orientation aligned parallel to the light-transmissive conductive substrate by the orientation layer, while the liquid crystal polymer layer remains in the parallel orientation, and the reflector can reflect both left-handed and right-handed circularly polarized light.

As the positive liquid crystal is used in the invention, the reflectivity of the reflector to the left circularly polarized light is reduced or even disappears under the action of an electric field, and the reflection influence to the right circularly polarized light is small, so that the reflectivity of the reflector to the unpolarized light is reduced to below 50 percent, and the reflectivity can be reversibly recovered to above 90 percent after the electric field is removed.

As shown in fig. 4 and 5, the temperature response of the reflector is based on the liquid crystal temperature range of the material. Because the main components of the small molecular liquid crystal layer are small molecular liquid crystal and the non-polymerizable chiral dopant with the left hand, when the temperature of the device is 25 ℃, the liquid crystal of the small molecular liquid crystal layer is in an anisotropic liquid crystal phase and is arranged parallel to the light-transmitting conductive substrate, and at the moment, the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light simultaneously. When the temperature of the reflector is raised to 50 ℃, the temperature is higher than the clearing point temperature of the micromolecular liquid crystal, the liquid crystal of the micromolecular liquid crystal layer is converted into an isotropic liquid state from an original anisotropic liquid crystal phase, the clearing point temperature is raised due to the existence of a polymer network in the liquid crystal polymer layer, molecules still maintain cholesteric phase arrangement parallel to the light-transmitting conductive substrate, and the reflector can only reflect right-handed circularly polarized light. When the temperature of the reflector is reduced to 25 ℃, the positive polarity is changed from the original isotropic liquid state into an anisotropic liquid crystal state, and is changed back to the orientation parallel to the light-transmitting conductive substrate, while the liquid crystal polymer layer still maintains the parallel orientation, and at the moment, the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light at the same time.

The polymerizable right-handed chiral liquid crystal monomer, the polymerizable liquid crystal monomer, the positive liquid crystal and the non-polymerizable left-handed chiral dopant are mixed together, the right-handed polymerizable chiral dopant dominates before non-illumination polymerization because the helical twisting force of the right-handed chiral monomer is larger, the left-handed twisting force is covered due to racemization, the reflector can only reflect right-handed circularly polarized light, and the reflectivity is less than 50%. The ultraviolet exposure causes the polymerizable monomer to be initiated at a faster rate at the side close to the light source (upper layer), so that the polymerizable monomer diffuses to the side close to the light source, resulting in the upper layer forming a right-handed liquid crystal polymer layer. Meanwhile, the right-handed polymerizable monomer diffuses to the upper layer, so that the left-handed chiral dopant is extruded to the side (lower layer) far away from the light source, and the content of the left-handed chiral dopant in the lower layer is higher, so that a left-handed small molecule liquid crystal layer is formed in the lower layer.

The invention realizes the coexistence of two components with opposite chirality in ultraviolet illumination polymerization, avoids racemization, thereby reflecting two kinds of circularly polarized light in rotation directions and improving the reflectivity of the reflector; the invention forms a liquid crystal polymer layer and a small molecular layer after ultraviolet irradiation polymerization, has good compatibility, and does not precipitate substances due to poor solubility; meanwhile, the invention has good stability, and the device can reflect two handedness circular polarized lights after ultraviolet illumination polymerization, and can reversibly return to the initial state and stably exist after heating and electrifying. Meanwhile, in order to meet the actual requirement, the invention can adjust the wave band position of the reflection peak according to the concentration of the chiral dopant, so that the reflector has super reflection (the reflectivity is more than 90%) in the visible light wave band and the infrared light wave band.

The invention can adjust the wave band position of the reflection peak according to the concentration of the chiral dopant, so that the reflector has the functions of super reflection (the reflectivity is more than 90 percent), temperature response and electric response in the visible light wave band and the infrared light wave band. The small molecular layer is changed from a cholesteric liquid crystal state with anisotropy into an isotropic state through heating, so that the small molecular layer cannot reflect left-handed circularly polarized light, or the small molecular layer is changed from a cholesteric liquid crystal state with a parallel texture into a scattering state through an electrification method, so that the ability of the small molecular layer to reflect the left-handed circularly polarized light is weakened, and the two processes are reversible processes, so that the regulation and control of transmitted light are realized. The invention has the advantages of easily obtained required materials, simple and feasible preparation process, short time consumption of the preparation process and excellent performance, and can be applied to industrial production by using lower-cost materials and simple preparation flow.

The reflector disclosed by the invention has the characteristics of high reflectivity and heating or electrifying adjustable rotating direction of reflected light, and specifically comprises the following components: because the chiral directions of the liquid crystal polymer layer and the small molecule liquid crystal layer are opposite, the reflector can reflect left-handed circularly polarized light and right-handed circularly polarized light at room temperature in an unpowered state, and the reflector has a super-reflection effect. The small molecular liquid crystal layer is regulated and controlled, the reflector is heated or an electric field is applied to the reflector, the small molecular liquid crystal layer is changed into an isotropic state by heating, the orientation of the small molecular liquid crystal layer is changed into a zoom cone state by electrifying, the liquid crystal polymer layer is hardly influenced, the reflector cannot reflect left-handed circularly polarized light at the moment, the reflectivity of the reflector is less than 50%, and the super-reflection effect is avoided. And the temperature is reduced to room temperature or the electric field is removed, the small molecular liquid crystal layer returns to the initial state, the small molecular liquid crystal layer can reflect left-handed circularly polarized light at the moment, the liquid crystal polymer layer reflects right-handed circularly polarized light, the reflectivity of the reflector is more than 90%, and the reflector realizes a super-reflection effect. Wherein, the reflection waveband of the reflector can be realized by adjusting the type or content of the chiral raw material in the liquid crystal mixture.

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.