TW202219557A - Smart window - Google Patents

Abstract

A smart window is used to solve a problem of complex structure and poor switching effect of the conventional smart window. The smart window includes two substrates and a light adjusting layer. The two substrates are electrically connected to a voltage source respectively, for forming a switchable electrical field therebetween. The light adjusting layer is a liquid crystal material filling up between the two substrates. The liquid crystal material contains a chirality molecule, a dichroic dye and a salt ion mixed in a nematic liquid crystal. A weight percentage concentration of the chirality molecule in the liquid crystal material is determined by a constraint. The constraint is expressed as

, where C is the weight percentage concentration, n is the birefringence rate of the liquid crystal material, p is the helical twisting power of the chirality molecule, D is the thickness of the light adjusting layer, m ₁is a constant of multiaxial absorption condition, and m ₂is a constant of normally transparent condition.

Description

Smart Windows

The present invention relates to a photoelectric element, in particular to a smart window capable of switching transparency, absorbing and scattering light.

Ordinary windows allow light to pass through, and are used to increase indoor lighting or expand the field of view through windows, while existing smart windows can be switched to light absorption or light scattering modes, so that the windows can be switched to shading without filming or matching curtains , heat insulation and block vision and other multifunctional purposes.

The above-mentioned conventional smart windows are limited by material compatibility and switching conditions, and cannot use a single-structure smart window to control light to perform multi-functional switching of transparency, absorption, and scattering, resulting in poor dimming effect of the conventional smart window. Limited use. In addition, combining two types of smart windows with different effects can increase switchable functional options. However, the multi-layer structure of smart windows leads to problems such as heavy products, increased manufacturing costs, and increased control difficulty.

In view of this, the conventional wisdom window does still need to be improved.

In order to solve the above problems, the purpose of the present invention is to provide a smart window that can simply and quickly switch the states of light transparency, light absorption and light scattering.

The second objective of the present invention is to provide a smart window that does not require a multi-layer structure such as a polarizer, and is simple to manufacture and easy to operate.

Another object of the present invention is to provide a smart window, which can improve the effect of switching functions such as light transmission, shading, heat insulation and astigmatism.

The use of the quantifier "a" or "an" for the elements and components described throughout the present invention is only for convenience and provides a general meaning of the scope of the present invention; in the present invention, it should be construed as including one or at least one, and a single The concept of also includes the plural case unless it is obvious that it means otherwise.

，其中，C為該重量百分濃度，n為該液晶材料之雙折射率，p為該旋性分子之旋性力，D為該調光層之厚度，m ₁為一多軸吸收之邊界常數，m ₂為一常態透明之邊界常數。 The smart window of the present invention comprises: two substrates, respectively electrically connected to a voltage source to form a switchable electric field between the two substrates; and a dimming layer filled between the two substrates by a liquid crystal material, The liquid crystal material is composed of a rotational molecule, a dichroic dye and a salt ion mixed in a nematic liquid crystal. The weight percentage concentration of the rotational molecule in the liquid crystal material is determined according to a restriction formula. The restriction formula is: :

, where C is the weight percent concentration, n is the birefringence of the liquid crystal material, p is the rotational force of the rotational molecule, D is the thickness of the dimming layer, and m ₁ is the boundary of a multiaxial absorption constant, m ₂ is a constant transparent boundary.

Accordingly, the smart window of the present invention can control the arrangement effect of the rotational force on the liquid crystal molecules under the action of different voltages through the restriction formula of the concentration of the rotational molecules of the liquid crystal material. It has the functions of reducing manufacturing difficulty, switching light states simply and quickly, and improving the dimming effect.

The boundary constant of the multiaxial absorption is 0.56, and the boundary constant of the normal transparency is 0.8. In this way, the numerical values of the boundary constant of multiaxial absorption and the boundary constant of normal transparency are obtained through experimental measurement samples, and the formula ratio of the liquid crystal material can be directly calculated, which has the effect of simple and rapid preparation of the liquid crystal material.

Wherein, when no voltage is applied to the two substrates, the liquid crystal molecules of the liquid crystal material exhibit a continuous arrangement perpendicular to the two substrates from top to bottom, and the dimming layer is in a transparent state. In this way, the smart window can be kept transparent most of the time without power consumption, and has the effects of power saving and lighting when power is off.

When a first voltage is applied to the two substrates, the liquid crystal molecules of the liquid crystal material exhibit a super-twisted nematic arrangement, the liquid crystal material absorbs incident light in different polarization directions, and the light-adjusting layer is in an absorption state. In this way, the liquid crystal material can be controlled to absorb various polarized components in natural light, and has the effect of increasing the effect of shading and heat insulation.

Wherein, the liquid crystal material is mixed with a specific dichroic dye to increase the absorptivity of the light-adjusting layer to light of a specific wavelength. In this way, the liquid crystal material can selectively absorb visible light or ultraviolet light, etc., and has the effect of selectively isolating harmful light.

Wherein, by adjusting the magnitude of the first voltage, the light absorption rate of the dimming layer is changed. In this way, the smart window can adjust the gray scale of the incident light, and has the effect of adjusting the light transmission intensity and brightness.

When a second voltage is applied to the two substrates, the salt ions interfere with the liquid crystal molecules of the liquid crystal material to present discontinuous and chaotic arrangement, the incident light is dispersed in the light adjustment layer, the light adjustment layer is in a scattering state, and the light adjustment layer is in a scattering state. The second voltage is greater than the first voltage. In this way, the smart window can further disperse the incident light and blur the image, which has the effect of blurring the field of view and protecting privacy.

The haze value of the light-adjusting layer is changed by adjusting the magnitude of the second voltage. In this way, the smart window can control the scattering phenomenon of the incident light, and has the effect of controlling the light transmittance and affecting the degree of blurring.

Wherein, each of the substrates includes a conductive layer, and the two conductive layers are respectively electrically connected to a voltage source, and the two conductive layers are indium tin oxide, nano-silver wire or transparent conductive metal. In this way, the proportion of incident light absorbed by the conductive layer can be reduced, and the difference between the transparent state and the absorption state can be increased.

Wherein, each of the substrates includes an alignment layer, and the included angle between the pretilt angle of each alignment layer and the plane of the substrate is greater than 85 degrees, and the two alignment layers are polyimide films. In this way, the two alignment layers can form several aligned grooves facing the liquid crystal material, which has the effect of vertically aligning the liquid crystal molecules.

In order to make the above-mentioned and other objects, features and advantages of the present invention more obvious and easy to understand, the preferred embodiments of the present invention are exemplified below, and are described in detail as follows in conjunction with the accompanying drawings:

Please refer to FIG. 1 , which is a preferred embodiment of the smart window of the present invention, which includes two substrates 1 and a light-adjusting layer 2 , and the light-adjusting layer 2 is located between the two substrates 1 .

The two substrates 1 are preferably parallel to each other, and the two substrates 1 are preferably made of transparent composite materials, so that light can penetrate the two substrates 1. Each of the substrates 1 further includes a conductive layer 11 and an alignment layer 12. The two conductive layers 11 are respectively electrically connected to a voltage source, which can form a switchable electric field between the two substrates 1 ; in addition, the two alignment layers 12 are respectively located inside the two substrates 1 , and the alignment layers 12 are The included angle between the pretilt angle and the plane of the substrate 1 is greater than 85 degrees. Each of the substrates 1 may contain a sealed material, such as glass, acrylic, plastic, etc., for confining fluid substances between the two substrates 1 ; the two conductive layers 11 may be transparent conductive materials, such as indium tin oxide (ITO), nano-silver wire, transparent conductive metal, etc., as the electrodes at both ends of the electric field between the two substrates 1; the two alignment layers 12 can be polyimide (Polyimide, PI) thin films, by forming on the surface Several directional grooves produce directional effects.

其中，C為該重量百分濃度，n為該液晶材料21之雙折射率，p為該旋性分子之旋性力，m ₁為一多軸吸收之邊界常數（Constant of Multiaxial Absorption Condition），m ₂為一常態透明之邊界常數（Constant of Normally Transparent Condition），該多軸吸收之邊界常數m ₁及該常態透明之邊界常數m ₂的數值係透過實驗量測樣本得知，

，

。 The light-adjusting layer 2 is filled between the two substrates 1 by a liquid crystal material 21 , so that a thickness D of the light-adjusting layer 2 is the distance between the two substrates 1 , and the liquid crystal material 21 is composed of a rotational molecule , a dichroic dye and a salt ion are mixed in a nematic liquid crystal to form, wherein the liquid crystal material 21 has anisotropic dielectric properties, and the rotational molecule has a helical twisting force (Helical Twisting Power , HTP), the range of the weight percent concentration (Weight Percentage Concentration) of the rotational molecule in the liquid crystal material 21 is limited by the following formula:

Wherein, C is the weight percent concentration, n is the birefringence of the liquid crystal material 21, p is the rotational force of the rotational molecule, m ₁ is a constant of Multiaxial Absorption Condition, m ₂ is a constant of normally transparent boundary (Constant of Normally Transparent Condition), the value of the boundary constant m ₁ of multi-axis absorption and the boundary constant m ₂ of normal transparency are obtained through experimental measurement samples,

,

.

Referring to FIG. 2a, when no voltage is applied to the light-adjusting layer 2, the two alignment layers 12 act on the light-adjusting layer 2 in a homeotropic alignment (Homeotropic Alignment) from the upper and lower sides, respectively, so that the liquid crystal material The liquid crystal molecules of 21 are in a continuous arrangement perpendicular to the two substrates 1 from top to bottom, and the incident light can directly pass through the liquid crystal molecules arranged neatly. effect.

Referring to FIG. 2b, when a first voltage V1 is applied to the light-adjusting layer 2, the liquid crystal material 21 is subjected to a high twisting force, causing the liquid crystal molecules to exhibit a Super Twisted Orientation. The liquid crystal material 21 can absorb incident light with different polarization directions, and mixing a specific dichroic dye system can increase the absorption rate of light of a specific wavelength. Since most of the incident light is absorbed by the liquid crystal material 21, the dimming layer 2 It is an absorption state, which has the function of shading and heat insulation. In addition, by adjusting the magnitude of the first voltage V1, the light absorptivity of the light-adjusting layer 2 can be changed, which has the effect of adjusting the gray scale of the light.

Referring to FIG. 2c, when a second voltage V2 is applied to the dimming layer 2, wherein the second voltage V2 is greater than the first voltage V1, under the action of a larger electric field, the liquid crystal material 21 Contains the salt ions, resulting in the occurrence of Electrohydrodynamic Effect, which makes the liquid crystal molecules appear discontinuous and chaotically arranged. 2 is a scattering state, which has the effect of blurring vision and protecting privacy. In addition, by adjusting the magnitude of the second voltage V2, different degrees of scattering effects can be exhibited, and the haze value of the light-adjusting layer 2 can be changed.

In the manufacturing process of the smart window of the present invention, the distance between the two substrates 1 can be determined first, and the type of the nematic liquid crystal and the tactical molecule of the liquid crystal material 21 can be selected, so that the dimming can be known. The thickness D of the layer 2, the birefringence n of the liquid crystal material 21, and the rotational force p of the rotational molecule are then determined by the above-mentioned known multiaxial absorption boundary constant m ₁ and normal transparency boundary constant m ₂ and the limiting formula of the weight percent concentration C, it is possible to calculate the appropriate concentration of the rotatory molecules mixed in the liquid crystal material 21, so that the light-adjusting layer 2 exhibits high transmittance in the transparent state and is effective in the absorption state It absorbs multi-axis light effectively, which has the function of simplifying the process and improving the dimming effect.

，經計算可得：

，係可以決定該旋性分子的濃度範圍，進而簡單且快速地製造出多功能切換的智慧窗戶。 In one embodiment, the thickness D of the light-adjusting layer 2 is 8 microns, the liquid crystal material 21 is selected to use a negative liquid crystal HNG707700-100 with a birefringence n of 0.1, and a rotatory molecule with a rotatory force p of 10 R811, substitute the above parameters into the restriction formula of the weight percent concentration C:

, which can be calculated by:

, the system can determine the concentration range of the rotatory molecule, and then simply and quickly create a multifunctional switchable smart window.

To sum up, the smart window of the present invention can control the alignment effect of the rotational force on the liquid crystal molecules under the action of different voltages through the restriction formula of the concentration of the rotatory molecules of the liquid crystal material, which can be transparent in a normal state, and can absorb polarization in multiple directions. It has the functions of reducing the difficulty of manufacturing, switching the light state simply and quickly, and improving the dimming effect.

Although the present invention has been disclosed by the above-mentioned preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications relative to the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the patent application attached hereto.

1: Substrate 11: Conductive layer 12: Alignment layer 2: Dimming layer 21: Liquid crystal material D: thickness V1: first voltage V2: The second voltage

[Figure 1] An exploded perspective view of a preferred embodiment of the present invention. [Fig. 2a] A situation diagram of transparent state switching in a preferred embodiment of the present invention. [FIG. 2b] A diagram showing the switching situation of the absorption state according to the preferred embodiment of the present invention. [Fig. 2c] A situation diagram of the switching of the scattering state according to the preferred embodiment of the present invention.

1: Substrate

11: Conductive layer

12: Alignment layer

2: Dimming layer

21: Liquid crystal material

Claims (10)

A smart window, comprising: two substrates, respectively electrically connected to a voltage source to form a switchable electric field between the two substrates; and a dimming layer filled between the two substrates by a liquid crystal material, the liquid crystal The material is composed of a rotatory molecule, a dichroic dye and a salt ion mixed in a nematic liquid crystal, and the weight percentage concentration of the rotatory molecule in the liquid crystal material is determined according to a restriction formula. The restriction formula is:

, where C is the weight percent concentration, n is the birefringence of the liquid crystal material, p is the rotational force of the rotational molecule, D is the thickness of the dimming layer, and m ₁ is the boundary of a multiaxial absorption constant, m ₂ is a constant transparent boundary. The smart window of claim 1, wherein the boundary constant of the multi-axis absorption is 0.56, and the boundary constant of the normal transparency is 0.8. The smart window of claim 1, wherein when no voltage is applied to the two substrates, the liquid crystal molecules of the liquid crystal material present a continuous arrangement perpendicular to the two substrates from top to bottom, and the dimming layer is in a transparent state. The smart window of claim 1, wherein when a first voltage is applied to the two substrates, the liquid crystal molecules of the liquid crystal material exhibit a super-twisted nematic arrangement, the liquid crystal material absorbs incident light in different polarization directions, and the light adjustment layer is an absorbing state. The smart window of claim 4, wherein the liquid crystal material is mixed with a specific dichroic dye to increase the absorption rate of the light adjustment layer for a specific wavelength of light. The smart window of claim 4, wherein the light absorption rate of the dimming layer is changed by adjusting the magnitude of the first voltage. The smart window of claim 4, wherein when a second voltage is applied to the two substrates, the salt ions interfere with the liquid crystal molecules of the liquid crystal material to present a discontinuous and chaotic arrangement, the incident light is dispersed in the light adjustment layer, the adjustment The optical layer is in a scattering state, and the second voltage is greater than the first voltage. The smart window of claim 7, wherein the haze value of the dimming layer is changed by adjusting the magnitude of the second voltage. The smart window of claim 1, wherein each of the substrates includes a conductive layer, and the two conductive layers are respectively electrically connected to a voltage source, and the two conductive layers are indium tin oxide, nano-silver wire or transparent conductive metal. The smart window of claim 1, wherein each of the substrates comprises an alignment layer, the pretilt angle of each of the alignment layers and the included angle of the plane of the substrate is greater than 85 degrees, and the two alignment layers are polyimide films.

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