TWI464493B - Light adjusting structure - Google Patents

Description

Dimming structure

The present invention relates to an optical structure, and more particularly to a dimming structure that modulates the amount and color of light.

Because smart glass has the advantage of reducing heat radiation to save energy, it has been widely used in offices, residential buildings, green buildings and large commercial sites. The coatings used in smart glass can be divided into static and dynamic according to the adjustment method.

Static smart glass contains the following categories: metal oxide coatings, photochromic coatings, and thermochromic films. Metal oxide coatings utilize the properties of metal compounds to allow visible light to penetrate while reflecting infrared and far infrared radiation to block heat transfer, but have the disadvantage of low incident light transmission. In order to improve this disadvantage, high refractive materials are required, so this type of smart glass is costly. Photochromic coatings use light-sensitive and reversible chemical materials such as silver chloride (AgCl), but these light-sensitive materials are slower to discolor and are currently only used in sunglasses. The thermochromic film is composed of two polarizing films having a vertical absorption axis and a liquid crystal layer between the two polarizing films. The liquid crystal molecules in the liquid crystal layer are extremely sensitive to temperature, so at a high temperature Liquid crystal molecule It exhibits the characteristics of isotropic, so it can effectively reduce the penetration of incident light in a high temperature environment. However, at present, this type of thermochromic film is difficult to mass-produce due to the width of the polarizing film and the limitation of the bonding technology.

In order to solve the above problems and the like, the present invention proposes a dimming structure, which can achieve large-scale production of roll to roll, and adjust the color of light entering the room according to the needs of different customers; and can further cover On a transparent hard substrate, such as glass, sunglasses or automotive glass, to achieve the effect of regulating the amount of light.

According to an aspect of the present invention, a dimming structure includes a first polarizing film; a phase retarding film disposed on the first polarizing film; and a polymer dispersed liquid crystal film (PDLC film). And being disposed on the phase retardation film; and a second polarizing film disposed on the polymer dispersed liquid crystal film.

According to an embodiment of the present invention, since the absorption axis angles of the first polarizing film and the second polarizing film are the same, an angle between an absorption axis of the first polarizing film and the second polarizing film and a slow axis of the phase retardation film It is 45 degrees, and the slow axis of the phase retardation film is perpendicular to the alignment direction of the polymer dispersed liquid crystal film.

According to an embodiment of the invention, the first polarizing film comprises a a first polarizer and a first outer protective film, and the first outer protective film is located at an outermost side of one of the light control structures.

According to an embodiment of the present invention, the phase retardation film is provided between the first polarizer and the polymer dispersed liquid crystal film.

According to an embodiment of the invention, the first polarizing film further includes a first inner protective film, wherein the first inner protective film is disposed between the phase retardation film and the first polarizer.

According to an embodiment of the invention, the second polarizing film comprises a second polarizer and a second outer protective film, and the second outer protective film is located at the other outermost side of the light adjusting structure.

According to an embodiment of the present invention, the polymer dispersed liquid crystal film is provided between the phase retardation film and the second polarizer.

According to an embodiment of the present invention, the second polarizing film further includes a second inner protective film, wherein the second inner protective film is disposed between the polymer dispersed liquid crystal film and the second polarizer.

According to an embodiment of the present invention, the polymer dispersed liquid crystal film and the phase retardation film have the same in-plane retardation value R ₀ (in-plane retardation).

According to an embodiment of the present invention, the protective layer is a transparent flexible substrate.

According to an embodiment of the present invention, the material of the transparent flexible substrate is polyethylene terephthalate (polyethylene terephthalate, PET), polycarbonate (PC), triacetyl cellulose (TAC), polymethyl methacrylate (PMMA), cyclo-olefin polymer (COP) or Its combination.

According to an embodiment of the present invention, the protective layer further has a hard-coating function, an anti-UV function, an anti-reflection function, an anti-glare function, and an anti-glare function. Anti-infrared function (Anti-IR), or a combination of functions.

According to an embodiment of the present invention, the polymer dispersed liquid crystal film is composed of a thermoplastic resin (Thermosetting resin) and a liquid crystal material.

According to an embodiment of the present invention, the liquid crystal material is a thermotropic liquid crystal.

According to an embodiment of the present invention, the thermotropic liquid crystal is a Nematic LC, a Sematic LC, or a Cholesteric LC.

According to an embodiment of the present invention, the thermoplastic resin is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polycarbonate, and polyurethane. A group consisting of Polyurethane, Polyethylene terephthalate, Polyacrylic resin, Polyamide, and combinations thereof.

To further illustrate the technical features of this creation and the Efficacy, the preferred embodiments are described below, and in conjunction with the drawings, a detailed description is as follows:

In order to further illustrate the technical features of the present invention and the effects achieved, the preferred embodiments are described below in detail with reference to the accompanying drawings. The accompanying drawings are intended to be illustrative and not restrictive.

Please refer to FIG. 1A , which is a schematic cross-sectional view showing a conventional thermochromic film 100 . A conventional thermochromic film 100 includes a first polarizing film 110, a liquid crystal layer 120, and a second polarizing film 130.

Fig. 1B is a schematic axial view showing the polarizing film shown in Fig. 1A. The first polarizing film 110 has a first absorption axis 110A, and the second polarizing film 130 has a second absorption axis 130A, wherein the first absorption axis 110A and the second absorption axis 130A are perpendicular to each other. As shown in FIG. 1B, the first absorption axis 110A is substantially 0 degrees with respect to the horizontal line, and the second absorption axis 130A is substantially 90 degrees with respect to the horizontal line.

Next, please refer to Figure 1A and Figure 1B together. The conventional thermochromic film is irradiated from the first polarizing film 110 to form 90-degree polarized light in a normal temperature environment, and the 90-degree polarized light is converted into 0-degree polarized light by liquid crystal alignment in the liquid crystal layer 120. Finally, the second polarizing film 130 is penetrated. When the above conventional thermochromic film is at a high temperature In the environment, the liquid crystal layer 120 is affected by the temperature, and the liquid crystal molecules are no longer arranged in an orderly manner and become isotropic. Therefore, in a high temperature environment, the liquid crystal layer 120 cannot effectively convert all 90-degree polarized light into 0. When the polarized light is polarized, only part of the light can penetrate the second polarizing film 130, so that the effect of reducing light penetration is achieved.

It can be seen from the above that the two polarizing films required for the conventional thermochromic film have a vertical axis of absorption, so that the polarizing film can be first cut to a predetermined size during production, and then produced by sheet sticking.

In view of the above-mentioned problems of the prior art, the dimming film of the present invention is proposed. For a preferred embodiment, refer to the following.

2A is a cross-sectional structural view showing a light control structure 200 according to a preferred embodiment of the present invention. The dimming structure 200 includes a first polarizing film 210, a phase retardation film 220, a polymer dispersed liquid crystal film 230, and a second polarizing film 240. The phase retardation film 220 is disposed on the first polarizing film 210, the polymer dispersed liquid crystal film 230 is disposed on the phase retardation film 220, and the second polarizing film 240 is disposed on the polymer dispersed liquid crystal film 230. .

The phase retardation film 220 has an in-plane retardation value R ₀ (in-plane retardation), and its formula is as follows: R ₀ = (N _x - N _y ) d

N _x : a refractive index of the phase retardation film in the in-plane slow axis direction (x direction), N _y : a refractive index perpendicular to the in-plane (y direction) of the phase retardation film, and d: a thickness of the phase retardation film.

The in-plane phase retardation value R _{0 of the} phase retardation film 220 is the same as the in-plane phase retardation value of the polymer-dispersed liquid crystal film 230, and the R ₀ value ranges from 200 nm to 2500 nm, so that the controllable color type is equivalent. Many, such as red, pink, yellow, orange, green, blue, gray, or the color between them. According to an embodiment of the present invention, the phase retardation film 230 has an in-plane phase retardation value of 275 nm, which is a black dimming structure.

The polymer dispersed liquid crystal film 230 is composed of a polymer resin and a liquid crystal material. The polymer resin is a thermoplastic resin (Polysetting resin), and may be, for example, a polyolefin, a polyethylene, a polyvinyl chloride, a polystyrene, or a polycarbonate. A group consisting of Acrylic acid resin, Polyester, Polyamide, Polyurethane, or a combination thereof. The liquid crystal material is a Thermotropic Liquid Crystal. Thermotropic liquid crystals undergo phase change due to temperature changes, and can be classified into Nematic LC, Sematic LC, or Cholesteric LC according to the molecular structure and arrangement of liquid crystals. . The present invention is intended to be illustrative, and not to limit the scope of the invention.

At present, the main methods for preparing polymer-dispersed liquid crystal films are Temperature induced phase separation (TIPS) and solvent phase separation (Solvent induced phase). Separation, SIPS), Polymerization induced phase separation (PIPS), Microencapsulation process (MP) or cavitation method. However, the polymer-dispersed liquid crystal film used in the present invention is not limited to the above-described production method.

Figure 2B is an axial schematic view of the dimming structure of Figure 2A. The first polarizing film 210 has a first absorption axis 210A, the second polarizing film 240 has a second absorption axis 240A, and the first absorption axis 210A and the second absorption axis 240A have the same absorption axis angle. According to an embodiment of the invention, the first absorption axis 210A and the second absorption axis 240A are substantially 0 degrees with respect to the horizontal line. According to another embodiment of the present invention, the first absorption axis 210A and the second absorption axis 240A are substantially 90 degrees with respect to the horizontal line.

In FIG. 2B, the phase retardation film 220 has an optical slow axis 220S, and the angle between the first absorption axis 210A and the second absorption axis 240A is 45 degrees from the optical slow axis 220S. According to one embodiment of the invention, the optical slow axis 220S is substantially 45 degrees with respect to the horizontal.

In Fig. 2B, the liquid crystal molecules of the polymer-dispersed liquid crystal film 230 have an alignment direction 230L which is perpendicular to the optical slow axis 220S. According to an embodiment of the invention, the alignment direction 230L is substantially -45 degrees with respect to the horizontal line.

Next, please refer to FIG. 2A and FIG. 2B together to illustrate the actual mode of action of the dimming structure proposed by the present invention.

When the dimming structure shown in FIG. 2B is in a normal temperature environment, the incident light penetrates from the first polarizing film 210 to form a 90-degree linearly polarized light. Next, the phase retardation film 220 having the +45 degree optical slow axis 220S is penetrated, and then passed through the polymer dispersed liquid crystal film 230 having the -45 degree alignment direction 230L. Since the slow axis angle 220S of the phase retardation film 220 is opposite to the alignment direction 230L of the polymer dispersed liquid crystal film 230 and both have the same in-plane phase retardation value, the influence on the light can be canceled each other, so the light is maintained at 90 degrees. The linearly polarized light state finally penetrates the second polarizing film 240.

When the dimming structure shown in FIG. 2A is in a high temperature environment, the liquid crystal material in the polymer dispersed liquid crystal film 230 is affected by temperature and converted into an isotropic arrangement, so that it cannot cancel the phase retardation film 220, that is, It is said that light cannot be effectively converted back to 90 degree linearly polarized light. Therefore, the amount of light that finally penetrates the second polarizing film 240 is reduced, and the effect of adjusting the amount of light at a high temperature is achieved. Further, the color incident to the indoor light can be adjusted by the in-plane phase retardation value R _{0 of the} phase retardation film 220.

Further, the liquid crystal material in the polymer dispersed liquid crystal film 230 is converted into an isotropic arrangement in a high temperature environment. It is worth noting that the definition of the above "high temperature environment" will vary depending on the type of liquid crystal molecules used.

FIG. 3 is a cross-sectional structural view showing a light control structure 300 according to another preferred embodiment of the present invention. The dimming structure 300 includes a first polarizing film 310; a phase retarding film 320 disposed on the first polarizing film Above the film 310, a polymer dispersed liquid crystal film 330 is disposed on the phase retardation film 320; and a second polarizing film 340 is disposed on the polymer dispersed liquid crystal film 330.

The first polarizing film 310 includes a first polarizer 312 and a first outer protective film 311 , and the first outer protective film 311 is located at the outermost side of one of the dimming structures 300 . The second polarizing film 340 further includes a second polarizer 341 and a second outer protective film 342 , and the second outer protective film 342 is located on the other outermost side of the dimming structure 300 with respect to the first outer protective film 311 .

The protective films 311 and 342 are transparent flexible substrates, and the material thereof is, for example, polyethylene terephthalate (PET), polycarbonate (PC), triacetyl cellulose (TAC). ), polymethyl methacrylate (PMMA) and cyclo-olefin polymer (COP). In addition, the protective films 311 and 342 have a hard-coating function, an anti-UV function, an anti-reflection function, an anti-glare function, and an anti-infrared function ( Anti-IR), or a combination of functions.

FIG. 4 is a cross-sectional view showing the structure of a light control structure 400 according to another preferred embodiment of the present invention. The dimming structure 400 includes a first polarizing film 410, a phase retardation film 420 disposed on the first polarizing film 410, a polymer dispersed liquid crystal film 430 disposed on the phase retardation film 420, and a second polarizing film. Membrane 440, disposed on The polymer is dispersed on the liquid crystal film 430.

The first polarizing film 410 includes a first outer protective film 411, a first polarizer 412, and a first inner protective film 413. The first outer protective film 411 and the first inner protective film 413 are respectively disposed on the first polarizer 412. The second side. The second polarizing film 440 includes a second inner protective film 441, a second polarizer 442, and a second outer protective film 443. The second inner protective film 441 and the second outer protective film 443 are respectively disposed on the second polarizer 442. The second side.

The materials of the first outer protective films 311 and 411, the second outer protective films 342 and 443, the first inner protective film 413 and the second inner protective film 443 are transparent flexible substrates, and may be, for example, polyethylene terephthalate. (polyethylene terephthalate, PET), polycarbonate (PC), triacetyl cellulose (TAC), polymethyl methacrylate (PMMA), cyclo-olefin polymer (cyclo-olefin polymer, COP) or a combination thereof. The transparent flexible substrate further has a hard-coating function, an anti-UV function, an anti-reflection function, an anti-glare function, and an anti-infrared function (Anti- IR), or a combination of functions.

The materials of the first polarizers 312 and 412 and the second polarizers 341 and 442 are polyvinyl alcohol film (PVA). According to an embodiment of the present invention, a polyethylene film is immersed in an aqueous solution having iodine (Iodine, I ₂ ), potassium iodide (KI), and boric acid for stretching and dyeing to achieve polarization characteristics. . According to another embodiment of the invention, the polarizer uses a dye to achieve the effect of polarizing.

Since the modes of operation of the dimming structures 300 and 400 shown in FIGS. 3 and 4 are the same as those of the dimming structure 200 of FIG. 2A, they will not be described again.

The absorption axis angles of the first polarizing film and the second polarizing film of the conventional thermochromic film need to be perpendicular to each other, so that the polarizing film can be cut to a predetermined size first in production, and then produced by using a sheet sticker. The first polarizing film and the second polarizing film of the dimming structure proposed by the embodiments of the present invention have the same absorption axis angle, which facilitates large-scale roll to roll production in the process. And the utilization rate of the polarizing film is greatly improved when cutting. The color of the indoor light can be adjusted according to different customer needs.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧ thermochromic film

110, 210, 310, 410‧‧‧ first polarizing film

110A, 210A‧‧‧Axial axis of the first absorption shaft

120‧‧‧Liquid layer

130, 240, 340, 440‧‧‧ second polarizing film

130A, 240A‧‧‧Axial axis of the second absorption shaft

200, 300, 400‧‧‧ dimming structure

220, 320, 420‧‧‧ phase retardation film

Slow axis axial direction of 220S‧‧ phase retardation film

230,330,430‧‧‧ polymer dispersed liquid crystal film

Orientation direction of 230L‧‧‧ polymer dispersed liquid crystal film

311, 411‧‧‧ first outer protective film

312, 412‧‧‧ first polarizer

341, 442‧‧‧ second polarizer

342, 443‧‧‧ second outer protective film

413‧‧‧First inner protective film

441‧‧‧Second inner protective film

Fig. 1A is a schematic cross-sectional view showing a conventional thermochromic film.

Figure 1B is a schematic axial view of the film of Figure 1A.

2A is a dimming structure of an embodiment of the present invention Schematic diagram of the cross-section of 200.

Figure 2B is a schematic axial view of the film of Figure 2A.

FIG. 3 is a cross-sectional structural view showing a light control structure 300 according to an embodiment of the present invention.

FIG. 4 is a cross-sectional structural view showing a light control structure 400 according to another embodiment of the present invention.

200‧‧‧ dimming structure

210‧‧‧First polarizing film

220‧‧‧ phase retardation film

230‧‧‧ polymer dispersed liquid crystal film

240‧‧‧Second polarizing film

Claims (9)

a dimming structure comprising: a first polarizing film; a phase retarding film disposed on the first polarizing film; a polymer dispersed liquid crystal film disposed on the phase retarding film; a polarizing film disposed on the polymer dispersed liquid crystal film; wherein the first polarizing film and the second polarizing film have the same absorption axis angle, and the absorption axis of the first polarizing film and the second polarizing film The angle of the slow axis of the phase retardation film is 45 degrees, and the slow axis of the phase retardation film is perpendicular to the alignment direction of the polymer dispersed liquid crystal film, wherein the polymer dispersed liquid crystal film and the phase retardation film are in-plane. phase retardation value R ₀ (in-plane retardation) of the same line, and the phase retardation film in-plane phase retardation value R ₀ (in-plane retardation) based range between 200nm to 2500nm. The dimming structure of claim 1, wherein the first polarizing film comprises a first polarizer and a first outer protective film, wherein the first outer protective film is disposed in the dimming structure. The outermost side. Such as the dimming structure described in claim 2, The phase retardation film is disposed between the first polarizer and the polymer dispersed liquid crystal film. The dimming structure of claim 2, wherein the first polarizing film further comprises a first inner protective film, wherein the first inner protective film is disposed on the phase retarding film and the first polarizer between. The dimming structure of claim 1, wherein the second polarizing film comprises a second polarizer and a second outer protective film, wherein the second outer protective film is disposed on the dimming structure. One of the outermost sides. The dimming structure according to claim 5, wherein the polymer dispersed liquid crystal film is disposed between the phase retardation film and the second polarizer. The dimming structure of claim 5, wherein the second polarizing film further comprises a second inner protective film, wherein the second inner protective film is disposed on the polymer dispersed liquid crystal film and the second Between polarizers. The dimming structure according to claim 1, wherein the polymer dispersed liquid crystal film is composed of a thermotropic liquid crystal and a Made up of thermoplastic resin. The dimming structure according to claim 2, 4, 5 or 7 wherein the protective film is selected from the group consisting of polyethylene terephthalate (PET) and polycarbonate. a group consisting of a polyester (PC), a triacetyl cellulose (TAC), a polymethyl methacrylate (PMMA), and a cyclo-olefin polymer (COP), and These protective films are more hard-coating, anti-UV, anti-reflection, anti-glare, anti-infrared (Anti-IR). ), or a combination of functions.