KR20050069535A - Smart window using polymer dispersed liquid crystal - Google Patents

Abstract

The present invention provides a smart window using a polymer dispersed liquid crystal, a transparent substrate; A first electrode having a plurality arranged side by side on the transparent substrate; A plurality of second electrodes arranged side by side with the first electrode; It provides a smart window using a polymer dispersed liquid crystal and a method for manufacturing the same, comprising a polymer dispersed liquid crystal layer filled between the first and second electrodes.

The smart window using the polymer dispersion liquid crystal as described above can be configured at low cost by using a single transparent substrate, and in particular, various gray levels can be realized by variously modifying specific shapes of the first and second electrodes. There is this.

Description

Smart window using polymer dispersed liquid crystal and manufacturing method thereof {smart window using polymer dispersed liquid crystal}

The present invention relates to a smart window using a polymer dispersed liquid crystal (PDLC), and more particularly, includes a plurality of parallel first and second electrodes arranged alternately on one transparent substrate. And it relates to a smart window using a polymer dispersion liquid crystal that can implement a variety of different gray levels.

Conventional methods for controlling the transmittance of sunlight entering the room through ordinary glass include the deposition of metal oxides on the surface of glass using colored glass with colored oxides added to the glass composition or physical / chemical thin film deposition. The technique is known.

However, the glass produced in this way has no active control of sunlight, but is passive only with selective shielding or transmission capability for a certain wavelength range.

Recently, a so-called smart window has been developed as an active product capable of artificially controlling the light transmittance and color of glass, and is currently recognized as one of the next generation products in the glass field.

Smart window is obtained through the development of various thin film materials and the study of liquid crystal properties. Although it can be classified into various types according to the type of material, the smart window using polymer dispersed liquid crystal (PDLC) that is closest to the large size Smart windows are widely used.

Smart windows using polymer dispersion liquid crystals use the phenomenon that the whole becomes an opaque creamy phase when forcibly mixing two kinds of liquids which are transparent but do not dissolve together and have different refractive indices. Not only does each liquid in opaque become effective but also the effect of light scattering at their interface due to different refractive indices of the two liquids

1 is a cross-sectional view of a smart window using a general polymer dispersion liquid crystal, in which two substrates each having an electric field generating electrode are arranged in parallel on one surface facing each other, and then a polymer dispersion liquid crystal, which is a mixture of polymer and liquid crystal, is disposed therebetween. It is comprised through a layer.

That is, a smart window using a general polymer dispersed liquid crystal has two transparent substrates 2 and 4 facing each other with a constant gap, and a first deposited on the surface of each of the transparent substrates 2 and 4 facing each other. And second transparent electrodes 6 and 8. A polymer dispersion liquid crystal layer 10 including liquid crystal particles 14 and a polymer solution 12 that is a photosensitive material is interposed between the first and second transparent electrodes 6 and 8. It can be formed by coating the polymer solution 12 containing the liquid crystal particles 14 on any one of the substrate (2, 4).

When the smart window is exposed to ultraviolet rays, a photopolymerization reaction occurs in the polymer dispersion liquid crystal layer 10 to cause phase separation between the liquid crystal particles 14 and the photosensitive material polymer. A plurality of pores are generated in the liquid crystal layer 10, and the liquid crystal particles 14 are included in the pores.

In the V _off state where no voltage is applied to the first and second electrodes 6 and 8, light does not pass through a random arrangement of the polymer molecules surrounding the liquid crystal particles 14 and the liquid crystal particles 14. and is not scattered while uncertain, is arranged opposed to the have the first and second electrodes (6,8) in case of applying the voltage V to the liquid crystal state _on the particles (14) of the polymer to the polarization constant regularity, thereof Like the transmission axis, polymer molecules are arranged to become transparent as light passes.

However, such a smart window using a polymer dispersion liquid crystal is essentially required for two transparent substrates (2, 4), and in particular, each of the transparent substrates (2, 4) is equipped with electrodes, so the manufacturing process is complicated and costly This has a big disadvantage.

In addition, since there are only two gray levels of two tones according to two states of V _on or V _off , the expression of halftones is virtually impossible. In this situation, smart windows that have been improved are urgently needed.

Accordingly, the present invention is to meet the above requirements, and provides a smart window and a method for manufacturing the same using a dispersed polymer liquid crystal that can be configured at a low cost through a simpler manufacturing process, and in particular can represent a variety of different gray levels. There is a purpose.

In order to achieve the above object, the present invention provides a smart window using a polymer dispersed liquid crystal, a transparent substrate; A first electrode having a plurality arranged side by side on the transparent substrate; A plurality of second electrodes arranged side by side with the first electrode; It provides a smart window using a polymer dispersed liquid crystal, characterized in that it comprises a polymer dispersed liquid crystal layer filled between the first and second electrodes.

In this case, the first and the second electrode is characterized in that the ITO or a conductive polymer material, the first and second electrode is characterized in that the cross-sectional shape of the triangle, square or trapezoid.

In another aspect, the present invention provides a method for manufacturing a smart window using a polymer dispersed liquid crystal, comprising the steps of: a) providing a transparent substrate; b) forming a plurality of first and second electrodes arranged on one surface of the transparent substrate in parallel with each other; c) providing a smart window using the polymer dispersed liquid crystal, comprising the step of interposing a polymer dispersed liquid crystal layer between the first and second electrodes on one surface of the transparent substrate.

In this case, step b) includes depositing thin films of the first and second electrode materials on one surface of the transparent substrate; Selectively exposing the first and second electrode material thin films by applying a photoresist to the thin film and then exposing and developing using a mask; Etching and removing the exposed first and second electrode material thin films; And removing the remaining photoresist.

In addition, the first and second electrodes are characterized in that the ITO or conductive polymer, the first and second electrodes are characterized in that the cross-sectional shape of the triangle, square or trapezoid, with reference to the accompanying drawings below The present invention will be described in more detail.

2 is a perspective view of a smart window using a polymer dispersion liquid crystal according to the present invention, in which a plurality of parallel first and second electrodes 26 and 28 are alternately arranged on one transparent substrate 22 and one surface thereof. And a polymer dispersion liquid crystal layer 30 filled therebetween.

In this case, the transparent substrate 22 may be made of a transparent material such as glass or quartz, but in the case of quartz, since the price is expensive, the transparent substrate 22 does not meet the object of the present invention. Preferably, ordinary insulating glass may be used.

The first and second electrodes 26 and 28 are arranged on one surface thereof, and the plurality of electrodes are alternately arranged side by side. Each of them is applied with a voltage having a different magnitude through a driving circuit (not shown). Indium Tin Oxide (ITO) or a transparent conductive polymer material, which is a transparent conductive metal, may be used.

In addition, the polymer dispersion liquid crystal layer 30 filled therebetween may have a form in which liquid crystal particles are randomly contained in the polymer solution, which is a photosensitive material, and the polymer solution includes the first and second electrodes 26 and 28. It may be completed by coating on one surface of the transparent substrate 22.

Therefore, the greatest feature of the present invention is to arrange the first and second electrodes 26 and 28 on one transparent substrate 22 by staggering the polymer dispersed liquid crystal layer 30 using a lateral electric field formed therebetween. In the case of referring to the foregoing description, the first and second electrodes 26 and 28 may be applied with different voltages to change the transparent state from the opaque original state. It can be changed as well.

Meanwhile, specific shapes of the first and second electrodes 26 and 28 of the smart window according to the present invention may be variously modified, and correspond to the cross-sectional views taken along the line III-III of FIG. 2. This will be described with reference to FIGS. 3A to 3C.

In this case, the same parts having the same role in FIGS. 3A to 3C are denoted by the same reference numerals, and redundant descriptions are omitted, and only the reference numerals of the first and second electrodes are attached to the lowercase letters a, b, and c to help distinguish them. .

First embodiment

The first and second electrodes 26a and 26b according to the first embodiment of the present invention shown in FIG. 3a are narrower in width as the cross-sectional shape rises from the transparent substrate 22, respectively, and collected at one point at the best point. Losing triangles.

In this case, when a voltage is applied to the first and second electrodes 26a and 26b, the transverse electric field formed between them is the same as the dotted arrow, which is gradually weakened as it is raised, so that the arrangement direction of the liquid crystal particles 34 is gradually changed. Eggplant gray levels will appear.

Therefore, by appropriately adjusting the inclination of the triangular shape of these first and second electrodes (26a, 26b) it is possible to adjust the intensity of the magnetic field according to the height in a variety of ways, thereby realizing more various gray levels, in particular the intermediate system Joe's sensitivity can be controlled.

Second embodiment

In the second embodiment of the present invention, as shown in Fig. 3B, the cross-sectional shape of each of the first and second electrodes 26b and 26c is rectangular.

Therefore, the lateral electric field appearing between them is constant despite the height difference as indicated by the dotted arrow. In this case, two gray levels appear according to the voltage on / off, and more various gray levels can be realized by adjusting the voltage size. Do.

Third embodiment

The third embodiment of the present invention is as shown in Fig. 3c, which is a combination of the two previous embodiments, which forms a trapezoid in the shape of a cross section for each of the first and second electrodes 26c and 28c.

In this case, the transverse electric field between the first and second electrodes 26c and 28c gradually decreases away from the transparent substrate 22, similar to the triangle described in the first embodiment, and thus is similar to the above-described embodiment. You can expect the effect.

On the other hand, each of the above embodiments is only a few examples of the present invention, according to the purpose, such that the cross-sectional shape of the first electrode 26 as a triangle and the cross-sectional shape of the second electrode 28 as a square, etc. It is apparent to those skilled in the art that any number of applications are possible, and that various gray levels can be implemented.

That is, the greatest feature of the present invention is polymer dispersion using a transverse electric field formed therebetween by arranging a plurality of side-by-side first and second electrodes 26 and 28 so as to be alternately arranged on one transparent substrate 22. By driving the liquid crystal, as long as it satisfies this, the specific shape of the first and second electrodes 26 and 28 can be modified as much as possible, and all of them should be within the scope of the present invention.

This is also the same in the method for manufacturing a smart window according to the present invention, Figure 4 is a flow chart showing the manufacturing method of the smart window according to the present invention in sequence, Figures 5a and 5b is a process state diagram, respectively. 5A and 5B correspond to a cross section of the III-III line of FIG. 2, and for convenience of description, the first and second electrodes are described as being rectangular in shape as described with reference to FIG. 3B. It is only mentioned a few times above for illustrative purposes only.

The method for manufacturing a smart window according to the present invention is first provided with a transparent substrate 22, as shown in Figure 5a. (St1)

Subsequently, a plurality of side-by-side first and second electrodes 26b and 28b are arranged on the transparent substrate 22 so as to alternate with each other to be in a state as shown in FIG. 4B. Specifically, a photolithography method may be used. (The positive method is explained as an example.)

That is, after depositing the first and second electrode material in a thin film on one surface of the transparent substrate 22, a photoresist, a photosensitive material is applied to the upper portion of the transparent substrate 22, a mask having a predetermined pattern is placed on the top and then irradiated with light from the top To cure the photoresist in the selected area. Subsequently, the first and second electrode material thin films may be selectively exposed by removing the cured photoresist, and then etching may be performed to selectively remove the first and second electrode materials exposed to the outside.

Finally, by removing the residual photoresist, the first and second electrodes 26b and 28b are constituted as shown, followed by the polymer dispersed liquid crystal layer 30 therebetween. According to the present invention, the polymer dispersion liquid crystal layer 30 may be substantially the same as the height of the first and second electrodes 26b and 28b.

The smart window using the polymer dispersion liquid crystal according to the present invention has the advantage of being able to be configured at low cost since the first and second electrodes are arranged on one transparent substrate, so that no other transparent substrate is required.

In addition, various gray levels may be realized by variously modifying specific shapes of the first and second electrodes, and in particular, since a simple manufacturing process is required, it may be more widely used.

1 is a cross-sectional view of a smart window using a common polymer dispersed liquid crystal.

Figure 2 is a perspective view of a smart window using a polymer dispersed liquid crystal according to the present invention.

3A is a cross sectional view taken along the line III-III of FIG. 2 in accordance with a first embodiment of the present invention;

3B is a cross sectional view taken along the line III-III of FIG. 2 in accordance with a second embodiment of the present invention;

3C is a cross sectional view taken along the line III-III of FIG. 2 in accordance with a third embodiment of the present invention;

Figure 4 is a manufacturing process flow chart of the smart window using the polymer dispersion liquid crystal according to the present invention.

Figure 5a and Figure 5b is a cross-sectional view of the manufacturing process of the smart window using the polymer dispersed liquid crystal according to the present invention, respectively.

<Brief description of the main parts of the drawing>

22: transparent substrate 26: first electrode

28: second electrode 30: polymer dispersion liquid crystal layer

32: polymer solution 34: liquid crystal particles

Claims (7)

As a smart window using a polymer dispersion liquid crystal, A transparent substrate; A first electrode having a plurality arranged side by side on the transparent substrate; A plurality of second electrodes arranged side by side with the first electrode; Smart window using a polymer dispersed liquid crystal, characterized in that it comprises a polymer dispersed liquid crystal layer filled between the first and second electrodes. The method of claim 1, The first and second electrodes are smart windows using a polymer dispersed liquid crystal, characterized in that the ITO or conductive polymer material. The method of claim 1, The first and second electrodes are a smart window using a polymer dispersed liquid crystal, characterized in that the cross-sectional shape of the triangle, square or trapezoid. As a method of manufacturing a smart window using a polymer dispersion liquid crystal, a) providing a transparent substrate; b) forming a plurality of first and second electrodes arranged on one surface of the transparent substrate in parallel with each other; c) A method of manufacturing a smart window using a polymer dispersed liquid crystal, comprising the step of interposing a polymer dispersed liquid crystal layer between the first and second electrodes on one surface of the transparent substrate. The method of claim 4, wherein B) depositing thin films of the first and second electrode materials on one surface of the transparent substrate; Selectively exposing the first and second electrode material thin films by applying a photoresist to the thin film and then exposing and developing using a mask; Etching and removing the exposed first and second electrode material thin films; Smart window manufacturing method using a polymer dispersion liquid crystal comprising the step of removing the remaining photoresist. The method of claim 4, wherein The first and second electrodes are ITO or a method of manufacturing a smart window using a polymer dispersed liquid crystal, characterized in that the conductive polymer. The method of claim 4, wherein The first and second electrodes are a smart window using a polymer dispersed liquid crystal, characterized in that the cross-sectional shape of the triangle, square or trapezoid.