WO2017101817A1

WO2017101817A1 - Infrared reflection device based on electrical response

Info

Publication number: WO2017101817A1
Application number: PCT/CN2016/110130
Authority: WO
Inventors: 周国富; 胡小文; 鞠纯; 李琛
Original assignee: 深圳市国华光电科技有限公司; 深圳市国华光电研究院
Priority date: 2015-12-17
Filing date: 2016-12-15
Publication date: 2017-06-22
Also published as: CN105676489B; CN105676489A

Abstract

An infrared reflection device based on electrical response and a preparing method therefor. A chiral doping agent, chiral monomers, a photoinitiator, an ultraviolet absorbent are mixed with negative liquid crystals to obtain a liquid crystal mixture (6), and the liquid crystal mixture (6) is filled between two light-transmissive substrates to which a voltage can be applied. Ultraviolet light irradiates a liquid crystal cell from one side of a first light-transmissive substrate (1), the photoinitiator drives, under the effect of the ultraviolet light, the chiral monomers to polymerize into a chiral polymer network (7), and the concentration of the generated chiral polymer network (7) has a concentration gradient, that is, the chiral monomer concentration has a concentration gradient, thereby forming a pitch gradient of a negative liquid crystal helical structure (3), being able to obtain a wide bandwidth for reflecting infrared light. The chiral polymer network (7) can capture impurity cations (5) in the liquid crystal mixture (6), and in the state that the substrates are powered on, the impurity cations (5) drive the chiral polymer network (7) to move such that the chiral monomer concentration gradient is decreased and the pitch gradient is decreased, thereby achieving the purpose of changing the bandwidth from wide to narrow.

Description

An infrared response device based on electrical response

Technical field

The present invention relates to infrared reflecting devices, and more particularly to an infrared reflecting device based on electrical response.

Background technique

The indoor environment of the building has a very close relationship with the health of the occupants. As a result, heating, ventilation, and air conditioning equipment are widely used to provide a humid indoor environment. With the use of these devices, not only has the carbon dioxide emissions increased, but it has had a very negative impact on the environment. As a result, building shell technology began to play an important role, and a large number of innovative methods began to emerge. Attempts have been made to install blinds, shutters, liquid crystal windows and inorganic coatings on the building's outer casing. However, these technologies can neither regulate the indoor temperature nor absorb and reflect visible light, and cannot meet the needs of people who want to change the indoor environment.

People began to pay attention to the design of the window, hoping to control the absorption and reflection of sunlight to achieve the comfortable indoor environment that people want. It has been found that infrared reflective sheets have transmission and reflection properties under voltage application, allowing them to transmit infrared light at low temperatures and reflect infrared light at high temperatures. A cholesteric infrared reflection narrow band can help reduce heat through the window. Making such a window can reflect the sun in the summer and the sun in the winter. It is transparent throughout the visible light area, requires no illumination, and saves energy. However, more than 75% of the light is infrared light. This shortcoming is not conducive to the widespread and widespread use of coated glass worldwide.

Summary of the invention

The technical problem to be solved by the present invention is to provide an infrared reflection device based on electrical response.

The technical solution adopted by the present invention is:

An infrared response device based on an electrical response, comprising: a first transparent substrate and a second transparent substrate disposed opposite to each other; and a power component, wherein the first transparent substrate is electrically connected to a positive electrode of the power component, The transparent substrate is electrically connected to the negative electrode of the power module, and the adjustment region is formed between the first transparent substrate and the second transparent substrate, and the adjustment region is filled with a liquid crystal mixture, and the liquid crystal The mixture includes a negative liquid crystal, a chiral dopant, a photoinitiator, an ultraviolet light absorber, and a chiral polymer network, wherein the chiral polymer network initiates polymerization of the chiral monomer by the photoinitiator a network-like chiral polymer, wherein the negative liquid crystal is dispersed in the chiral polymer network, and in a state where the first transparent substrate and the second transparent substrate are not energized, The chiral polymer network concentration decreases in a gradient from the first transparent substrate to the second transparent substrate, and the chiral monomer and the chiral dopant cause the negative liquid crystal to form a spiral structure , the chiral polymer network concentration Such that the pitch of the helical structure of the liquid crystal negative gradient distribution, the chiral cationic polymer network can trap impurities in the liquid crystal mixture in the first light transmitting substrate and the second transparent In a state where the optical substrate is energized, the cation moves to the second transparent substrate under the action of an electric field, and the chiral polymer network is moved to move to the second transparent substrate, so that the chiral polymer network The concentration gradient is reduced such that the pitch gradient of the negative liquid crystal helix is reduced.

Preferably, the negative liquid crystal exhibits a cholesteric helical structure.

Preferably, the chiral monomer is DB-335.

Preferably, the chiral dopant is S811.

Preferably, the photoinitiator is Irgacure-369 or Irgacure-651.

Preferably, a parallel alignment layer is spin-coated on the surfaces of the first transparent substrate and the second transparent substrate.

The invention also provides a method for preparing an infrared reflection device based on electrical response, comprising the following steps:

S1: preparing a first transparent substrate and a second transparent substrate, wherein the first transparent substrate and the second transparent substrate are oppositely disposed;

S2: spin-coating an alignment layer on a surface opposite to the first transparent substrate and the second transparent substrate, and rubbing the orientation;

S3: preparing the first transparent substrate and the second transparent substrate into a liquid crystal cell;

S4: weighing a negative liquid crystal, a chiral dopant, a chiral monomer, a photoinitiator, an ultraviolet light absorber, and heating to convert the liquid crystal into an isotropic liquid to obtain a liquid crystal mixture;

S5: injecting the liquid crystal mixture into the liquid crystal cell, the chiral monomer and the chiral dopant forming the negative liquid crystal to form a cholesteric spiral structure;

S6: ultraviolet light is irradiated from the side of the first transparent substrate to the liquid crystal cell, and the photoinitiator initiates polymerization of the chiral monomer to form a chiral polymer network, and the negative liquid crystal is dispersed in the hand In the polymer network, the ultraviolet light absorber causes a gradient of ultraviolet light intensity incident into the liquid crystal mixture such that the concentration of the chiral polymer network is from the first transparent substrate to the second The direction gradient of the transparent substrate is decreased, and then the pitch of the spiral structure is distributed in a gradient;

S7: The first transparent substrate is electrically connected to a positive electrode of the power component, and the second transparent substrate is electrically connected to a negative electrode of the power component.

Preferably, the mass ratio of the negative liquid crystal, the chiral dopant, the chiral monomer, the photoinitiator, and the ultraviolet light absorber in the liquid crystal mixture is (80-90): (3-13): ( 5-15): (0.1-0.8): (1-3).

Preferably, the chiral monomer is DB-335.

Preferably, the photoinitiator is Irgacure-369 or Irgacure-651.

The beneficial effects of the invention are:

The invention mixes a chiral dopant, a chiral monomer, a photoinitiator, an ultraviolet light absorber and a negative liquid crystal to obtain a liquid crystal mixture, and fills the liquid crystal mixture between two transparent substrates which can be connected to a voltage. Ultraviolet light from the first transparent substrate Irradiating the liquid crystal cell on one side, the photoinitiator initiates polymerization of the chiral monomer into a chiral polymer network under the action of ultraviolet light, and the concentration of the chiral polymer network generated has a concentration gradient, that is, the chiral single a concentration gradient exists in the bulk concentration, the chiral monomer and the chiral dopant forming the negative liquid crystal to form a helical structure, and the chiral polymer network concentration gradient is such that the pitch of the negative liquid crystal helical structure is Gradient distribution, the pitch is a gradient distribution to obtain a wide bandwidth of reflected infrared light. Wherein the chiral polymer network is capable of capturing impurity cations in the liquid crystal mixture, the impurity cations driving the chiral polymer network to move in a state where the substrate is energized, so that the concentration of the chiral polymer network in the liquid crystal mixture The difference is reduced, the chiral monomer concentration gradient is reduced, and the pitch gradient is reduced, thereby achieving the purpose of narrowing the reflection bandwidth from wide to narrow, thereby increasing the transmission of infrared light and increasing the indoor temperature; in the unpowered state, The chiral polymer network recovers its concentration gradient, so that the bandwidth of the reflected infrared light of the infrared reflecting device is widened, and the widening of the bandwidth can reduce the transmission of infrared light, which is favorable for reducing the indoor temperature.

DRAWINGS

Figure 1 is a schematic view showing the structure of a liquid crystal mixture injected into a liquid crystal cell;

2 is a cross-sectional view of the infrared reflecting device after ultraviolet light irradiation;

Figure 3 is a cross-sectional view of the infrared reflecting device in an energized state.

detailed description

The concept, the specific structure and the technical effects of the present invention will be clearly and completely described in conjunction with the embodiments and the accompanying drawings. It is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments, based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to The scope of protection of the present invention. In addition, all the coupling/joining relationships involved in the patents are not directly connected to the components, but rather may constitute a better coupling structure by adding or reducing the coupling accessories according to the specific implementation. The various technical features in the creation of the invention can be combined and combined without conflicting conflicts.

Example 1:

An infrared response device based on an electrical response is prepared by first preparing a first transparent substrate 1 and a second transparent substrate 8. The first transparent substrate 1 and the second transparent substrate 8 are oppositely disposed. And a surface of the first transparent substrate 1 and the second transparent substrate 8 are respectively spin-coated with a parallel alignment layer 2 and rubbed and oriented; the first transparent substrate 1 and the second transparent The light substrate 8 is prepared as a liquid crystal cell. Weighing negative liquid crystal, chiral dopant, chiral monomer, photoinitiator and ultraviolet light absorber into brown reagent bottle, the negative liquid crystal: chiral dopant: chiral monomer: photoinitiated Agent: the mass ratio of the ultraviolet light absorber is 83.8:5:10:0.2:1, uniformly mixed, heated to 70 ° C, and the liquid crystal is converted into an isotropic liquid state to obtain a liquid crystal mixture 6, each of which is The obtained material can be purchased on the market, wherein the negative liquid crystal is a nematic liquid crystal, the negative liquid crystal is LC-2079 of Merck & Co., Germany, and the chiral monomer is Merck of Germany. The company's DB-335, its structural formula is:

The chiral dopant is S811 of Merck & Co., Germany, and its structural formula is:

The photoinitiator is Irgacure-369 of Merck & Co., Germany, and its structural formula is:

The ultraviolet light absorber is Tinuvin 328 of Merck & Co., Germany.

Injecting the liquid crystal mixture 6 into the liquid crystal cell, the chiral monomer and the chiral dopant, the chiral monomer and the chiral dopant cause the negative liquid crystal to form a cholesteric type The spiral structure 3, under the action of the alignment layer, the axis of the spiral structure 3 is perpendicular to the first transparent substrate 1, and the structure of the liquid crystal mixture 6 in the liquid crystal cell is as shown in FIG.

Irradiating the liquid crystal cell from the side of the first transparent substrate 1 using ultraviolet light, the photoinitiator initiating polymerization of the chiral monomer to form a chiral polymer network 7, and the negative liquid crystal is dispersed in the In the chiral polymer network 7, the photoinitiator First, the negative liquid crystal, the chiral dopant, and the chiral monomer adjacent to the first transparent substrate 1 are polymerized under the action of ultraviolet light to form a chiral polymer network 7, due to being close to the first through The chiral monomer molecules of the optical substrate 1 are reduced, and the diffusion of chiral monomer molecules close to the second transparent substrate 8 is diffused toward the first substrate 1 so that the first transparent substrate 1 is The density of the chiral polymer network 7 is increased, and the concentration of the chiral polymer network 7 is gradually decreased from the first transparent substrate 1 to the second transparent substrate 8, and the ultraviolet light absorber is incident on the The intensity of the ultraviolet light in the liquid crystal mixture 6 is distributed in a gradient such that the concentration of the chiral polymer network 7 decreases from the direction of the first transparent substrate 1 to the second transparent substrate 8, that is, the chirality The concentration gradient of the monomers decreases, and the concentration gradient of the chiral polymer network 7 causes the pitch of the negative liquid crystal helix 3 to be in a gradient distribution. A cross-sectional view of the infrared reflecting device prepared by the above preparation method is shown in Fig. 2.

The chiral monomer in the liquid crystal mixture 6 forms a concentration difference according to the formula P=1/HTP×C, wherein P is a pitch, HTP is a helical twisting ability of a cholesteric liquid crystal, and C is a chiral monomer concentration. There is a concentration gradient, thereby forming a pitch gradient according to the formula: Δλ = Δn × P, where Δλ is the reflection wavelength, Δn is the average refractive index, and P is the pitch, since the pitch P of the helical structure 3 in the liquid crystal mixture 6 exists The gradient gives a wide bandwidth Δλ of reflected infrared light.

Further, the liquid crystal mixture 6 contains an impurity cation 5 and an impurity anion 4, and the chiral polymer network 7 can capture the impurity cation 5 in the liquid crystal mixture 6, and the chiral polymerization is performed in a state where the substrate is not energized. A schematic diagram of the object network 7 capturing the impurity cations 5 is shown in FIG. The first transparent substrate 1 is electrically connected to the positive electrode of the power component, and the second transparent substrate 8 is electrically connected to the negative electrode of the power component. The power component includes a DC power supply and is connected in series with DC. Voltage controller on the power supply. In a state where the first transparent substrate 1 and the second transparent substrate 8 are energized, a cross-sectional view of the infrared reflective device is as shown in FIG. 4, and the impurity cation 5 is moved toward the second transparent substrate 8 by an electric field, and is driven. The chiral polymer network 7 moves toward the second transparent substrate 8, thereby reducing the concentration gradient of the chiral polymer network 7, that is, the chiral monomer concentration gradient, according to the formula P=1/ HTP x C, it can be known that the decrease in the chiral monomer concentration gradient can reduce the pitch gradient of the helical structure 3. According to the formula Δλ=Δn×P, the pitch P gradient is decreased, so that the bandwidth Δλ of the reflected infrared light is narrowed, and the narrowing of the bandwidth can increase the transmission of infrared light, which is advantageous for raising the temperature. In the unpowered state, the chiral polymer network 7 returns to the original state as shown in FIG. 3, and restores its concentration gradient, so that the bandwidth of the reflected infrared light of the infrared reflecting device is widened, and the bandwidth is widened to reduce the infrared light. Transmission is conducive to lowering the temperature.

Example 2:

Example 2 is basically the same as Example 1, except that the photoinitiator is Irgacure-651 of TCI Company, and its structure is:

The negative liquid crystal: chiral dopant: chiral monomer: photoinitiator: the mass ratio of the ultraviolet light absorber is 80:3:5:0.1:1.

Example 3:

Example 2 is substantially the same as Example 1, except that the negative liquid crystal: chiral dopant: chiral monomer: photoinitiator: ultraviolet light absorber mass ratio is 90:13:15: 0.8:3.

Claims

An infrared response device based on an electrical response, comprising a first transparent substrate and a second transparent substrate and a power supply assembly disposed opposite to each other, wherein the first transparent substrate is electrically connected to the positive electrode of the power component The second transparent substrate is electrically connected to the negative electrode of the power module, and the first transparent substrate and the second transparent substrate are packaged to form an adjustment region, and the adjustment region is filled with a liquid crystal mixture. The liquid crystal mixture includes a negative liquid crystal, a chiral dopant, a photoinitiator, an ultraviolet light absorber, and a chiral polymer network, and the chiral polymer network is caused by the photoinitiator a network-like chiral polymer obtained by polymerizing a monomer, wherein the negative liquid crystal is dispersed in the chiral polymer network, and the first transparent substrate and the second transparent substrate are not energized The concentration of the chiral polymer network decreases from a direction of the first transparent substrate to the second transparent substrate, and the chiral monomer and the chiral dopant cause the negative The liquid crystal forms a spiral structure, and the chiral poly a concentration gradient of the network such that the pitch of the negative liquid crystal helical structure is in a gradient, the chiral polymer network capable of capturing impurity cations in the liquid crystal mixture, the first transparent substrate and the second transparent In a state where the optical substrate is energized, the cation moves to the second transparent substrate under the action of an electric field, and the chiral polymer network is moved to move to the second transparent substrate, so that the chiral polymer network The concentration gradient is reduced such that the pitch gradient of the negative liquid crystal helix is reduced.
The electrical response-based infrared reflective device according to claim 1, wherein the negative liquid crystal exhibits a cholesteric helical structure.
The electrical response based infrared reflective device of claim 1 wherein the chiral monomer is DB-335.
The electrical response based infrared reflective device of claim 1 wherein the chiral dopant is S811.
The electrical response-based infrared reflecting device according to claim 1, wherein the photoinitiator is Irgacure-369 or Irgacure-651.
The electrical response-based infrared reflective device according to claim 1, wherein a parallel alignment layer is spin-coated on a surface of the first transparent substrate and the second transparent substrate.
A method for preparing an infrared reflection device based on an electrical response, comprising the steps of:

S1: preparing a first transparent substrate and a second transparent substrate, wherein the first transparent substrate and the second transparent substrate are oppositely disposed;

S2: spin-coating an alignment layer on a surface opposite to the first transparent substrate and the second transparent substrate, and rubbing the orientation;

S3: preparing the first transparent substrate and the second transparent substrate into a liquid crystal cell;

S4: weighing a negative liquid crystal, a chiral dopant, a chiral monomer, a photoinitiator, an ultraviolet light absorber, and heating to convert the liquid crystal into an isotropic liquid to obtain a liquid crystal mixture;

S5: injecting the liquid crystal mixture into the liquid crystal cell, the chiral monomer and the chiral dopant making the negative The liquid crystal forms a cholesteric spiral structure;

S6: ultraviolet light is irradiated from the side of the first transparent substrate to the liquid crystal cell, and the photoinitiator initiates polymerization of the chiral monomer to form a chiral polymer network, and the negative liquid crystal is dispersed in the hand In the polymer network, the ultraviolet light absorber causes a gradient of ultraviolet light intensity incident into the liquid crystal mixture such that the concentration of the chiral polymer network is from the first transparent substrate to the second The direction gradient of the transparent substrate is decreased, and then the pitch of the spiral structure is distributed in a gradient;

S7: The first transparent substrate is electrically connected to a positive electrode of the power component, and the second transparent substrate is electrically connected to a negative electrode of the power component.
The preparation method according to claim 7, wherein the mass ratio of the negative liquid crystal, the chiral dopant, the chiral monomer, the photoinitiator, and the ultraviolet light absorber in the liquid crystal mixture is (80) -90): (3-13): (5-15): (0.1-0.8): (1-3).
The preparation method according to claim 7, wherein the chiral monomer is DB-335.
The method according to claim 7, wherein the photoinitiator is Irgacure-369 or Irgacure-651.