KR20160117326A - Smart window - Google Patents

Abstract

The present invention relates to a smart window. The smart window includes a first transparent substrate, a second transparent substrate, a first electrode, an insulation layer, a second electrode, fluid, and a driving body. Thereby, the smart window can control phototransmissivity at low driving voltage and can indicate rapid response speed.

Description

Smart Window {SMART WINDOW}

The present invention relates to a smart window.

Smart windows are used in windows, mirrors or display devices to control the transmission or reflectivity of light. Specifically, the smart window is applied to a window of a building or an automobile so that it can be controlled opaque so that the sunlight can be adjusted to be transparent to maximize the sunlight in winter and to block the sunlight in summer.

Conventionally, smart windows have been driven by SPD (Suspended Particle Devices), PDLC (Polymer Dispersed Liquid Crystal), and ECD (Electrochromic Device) methods. Recently, smart window related documents driven by ECD have been disclosed.

The present invention provides a smart window.

A smart window capable of adjusting the light transmittance through voltage application according to a specific embodiment of the present invention will be described.

According to an embodiment of the present invention, there is provided a liquid crystal display comprising: a first transparent substrate; A second transparent substrate disposed to face the first transparent substrate; A first electrode formed on one surface of a first transparent substrate facing the second transparent substrate; An insulating layer formed on a surface of the first electrode or a surface of the first transparent substrate on which the first electrode is formed and the first electrode; A second electrode formed on one surface of the second transparent substrate facing the first transparent substrate; A fluid filled between the insulating layer and the second electrode; And a driving body dispersed in the fluid in a non-driven state.

The smart window can control the light transmittance with a low driving voltage and exhibits a fast response speed. In addition, the smart window can be manufactured simply and economically and can be provided at a low cost.

Specifically, the smart window includes a first transparent substrate 11 as shown in FIGS. 1 and 2; A second transparent substrate (12) arranged to face the first transparent substrate; A first electrode (21) formed on one surface of a first transparent substrate facing the second transparent substrate; An insulating layer 31 formed on the first electrode 21 or the surface on which the first electrode 21 of the first transparent substrate 11 is formed and the first electrode 21; A second electrode (22) formed on one surface of a second transparent substrate facing the first transparent substrate; A fluid (32) filled between the insulating layer (31) and the second electrode (22); And a driving body 41 dispersed in the fluid 32 in a non-driving state of the smart window.

At the time of driving the smart window, at least a part of the driving body 41 dispersed in the fluid 32 can be agglomerated as shown in Fig. Accordingly, when the smart window is driven, the light incident on the smart window is blocked, and the smart window can be seen as opaque. On the other hand, when the smart window is not driven or reversely driven, as shown in FIG. 2, the coherent driving body 41 can be dispersed again in the fluid 32. [ Accordingly, when the smart window is not driven or reversed, the light incident on the smart window is transmitted through the driver 41, so that the smart window can be seen transparently.

Hereinafter, a structure according to one embodiment of the smart window will be described in detail with reference to FIGS. 1 to 3. FIG.

As shown in FIGS. 1 and 2, the smart window includes a first transparent substrate 11 and a second transparent substrate 12 arranged to face each other. As the first and second transparent substrates, a substrate having a transmittance of about 80% or more or about 85% or more with respect to light in a visible light region may be used so that light incident on the smart window is directly transmitted. Examples of the first and second transparent substrates include a glass substrate, a cycloolefin polymer (COP) such as triacetyl cellulose (TAC) and a norbornene derivative, a poly (methyl methacrylate), a polycarbonate (PC) polyetheretherketone (PEEK), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), poly (ethylene terephthalate), PI and a transparent polymer substrate formed of a polymer such as polyimide, polysulfone (PSF), polyarylate (PAR), or amorphous fluororesin. The materials of the first and second transparent substrates may be the same or different.

As shown in FIGS. 1 and 2, first and second electrodes 21 and 22 are formed on the first and second transparent substrates 11 and 12, respectively.

As the first and second electrodes, an electrode having a transmittance of about 80% or more or about 85% or more with respect to light in a visible light region may be used. Examples of such a transparent electrode include an electrode formed of a metal oxide having a high transmittance with respect to light in a visible light region such as ITO (Indium Tin oxide) or FTO (Fluorine-doped Tin oxide). However, the first and second electrodes are not limited to the above-described electrodes. Though not a transparent electrode, a metal electrode formed to have a thin thickness or patterned to minimize a decrease in transmittance can also be used. Examples of such a metal electrode include an electrode formed of a metal such as molybdenum (Mo), aluminum (Al), copper (Cu), or silver (Ag).

In the smart window according to the embodiment, the transmittance of light may be changed according to the voltage application due to the peculiarly patterned first electrode.

Specifically, the first electrode may be patterned to have a plurality of pad portions spaced apart from each other and a plurality of channel portions connecting the pad portions.

The pad unit may act to attract the driver when the smart window is driven and lower the light transmittance by the coherent driver. Accordingly, the pad portion can be formed in various shapes. As a non-limiting example, the pad portion may be formed as a polygonal or circular shape such as a triangle, a square and a pentagon, all formed in the same shape, or may be formed such that at least two arbitrarily selected shapes are different from each other. Such a pad portion can be formed in an appropriate size according to a desired light shielding degree. For example, the width of each pad portion in the first electrode may be adjusted to 1 μm ² to 250,000 μm ² . Within this range, a high light shielding degree can be realized with a fast response speed.

The channel portion may connect the pad portions spaced apart from each other to transmit a current to the entire pad portion. Such a channel portion may be formed in various shapes and may be formed in an appropriate size. Specifically, the channel portion may be formed to have a narrower width than the widest width of the pad portion. In one example, the width of the channel portion can be adjusted from 100 nm to 5 占 퐉. In addition, the length of the channel portion can be adjusted to about 1 to 500 mu m. Within this range, smart windows can be manufactured economically.

In one embodiment, the first electrode may be patterned as in FIG. Specifically, the plurality of pad portions 21a of the first electrode may be all square. Each of the pad portions 21a can be adjusted to have a length of 1 m to 500 m on one side and its width can be adjusted to 1 m ² to 250,000 m ² . The plurality of pad portions 21a are electrically connected by a plurality of channel portions 21b, and each channel portion may be formed to have a width of 100 nm to 5 占 퐉 and a length of 1 占 퐉 to 500 占 퐉.

An insulating layer is formed on a surface of the first electrode or the first electrode of the first transparent substrate and the first electrode. For example, if the first electrode is an unpatterned electrode, an insulating layer may be formed on the first electrode. 1 and 2, the insulating layer 31 is formed on the surface of the first transparent substrate 11 on which the first electrode 21 is formed and the surface of the first electrode 21 ) On a flat surface.

The insulating layer is formed on the first electrode or on the surface of the first transparent substrate on which the first electrode is formed and on the first electrode to prevent damage to the first electrode and short-circuiting.

The material for forming such an insulating layer is not particularly limited, and may be various materials known to those skilled in the art. For example, the insulating layer may be formed of silicon nitride, silicon oxide, or a mixture thereof. The above-described materials are suitable for economically providing smart windows of excellent overall performance.

The smart window may be formed by disposing the first and second transparent substrates so that the insulating layer and the second electrode face each other, and then sealing the first and second transparent substrates at a predetermined interval. The first and second transparent substrates may be encapsulated according to various methods known to those skilled in the art. A partition may be formed between the first and second transparent substrates so that an appropriate number of actuators may be present.

The fluid may be filled in the inner space obtained by sealing the first and second transparent substrates so as to be spaced apart from each other by a predetermined distance. The use of such fluids is less likely to cause problems such as coagulation due to electrical neutralization between the driving body particles, performance deterioration due to collision between the driving bodies, and deterioration of memory function. Further, the use of the fluid makes it possible to more easily move the driving body. For the purpose of this role, various fluids known in the technical field of the present invention can be used if they have a viscosity of about 10 to 5000 cP at about 25 캜. For example, the fluid furnace can be economically provided with a smart window of excellent performance by using silicone oil.

In the non-driven state of the smart window according to the embodiment, the fluid is dispersed in the fluid. The driving body is located between the insulating layer and the second electrode and may be charged particles so as to move by a voltage applied to the first and second electrodes. When the smart window is not driven, the driving body is widely distributed in the fluid. Accordingly, the light incident on the smart window passes through the drive body, and the smart window becomes transparent. On the other hand, the driving body is at least partially flocculated when the smart window is driven. More specifically, at the time of driving the smart window, at least a part of the driving body 41 dispersed in the fluid 32 may be concentrated on the pad portion 21a of the first electrode 21 as shown in Fig. 1 . The light incident on the smart window is blocked by the coherent driver so that the smart window becomes opaque. Then, when the smart window is placed in the non-driving or reverse driving state, the floated driving body is dispersed again to the fluid, and the smart window returns to the transparent state.

Accordingly, particles having a high shielding ratio can be used as the driving body. As an example, the driving body may include metal particles; Charged particles comprising a polymer and / or a metal oxide; Or carbon-based particles. More specifically, metal oxide particles such as TiO ₂ can be used as the charged particles, and graphene, carbon nanotubes, carbon nanofibers, carbon black, and the like can be used as the carbon-based particles. Among them, the titanium dioxide particles have an advantage of being able to prevent agglomeration due to high-speed response and electrical neutralization between particles.

In addition, the driving body is required to have an appropriate size because it shields the light when it is driven and blocks light when it is not driven or transmits the light when it is inversed or driven. For example, the driving body may be adjusted to have an average particle diameter of 100 nm to 10 mu m, 100 nm to 8 mu m, 100 nm to 5 mu m, or 100 nm to 1 mu m.

In such a range, it is possible to provide a smart window that exhibits a high light transmittance at the time of non-driving or reverse driving and repeatedly displays a low light transmittance at the time of driving.

Meanwhile, the smart window may further include a voltage unit, etc. employed in the technical field of the present invention to apply a voltage to the first and second electrodes so as to move the driving body. In addition, the smart window may further include a configuration that is conventionally employed in addition to the configuration described above according to the intended use.

The smart window according to an embodiment of the present invention can adjust the light transmittance even at a low driving voltage and exhibits a fast response speed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a section of a smart window in a driving state according to an embodiment; FIG.
Fig. 2 is a diagram schematically showing a cross section when the smart window of Fig. 1 is in a non-driving state.
3 is a diagram schematically showing a first electrode 21 patterned to have a pad portion 21a and a channel portion 21b as an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. However, this is provided as an example of the invention, and the scope of the invention is not limited thereto in any sense.

Example  1: Smart Windows  Produce

A smart window having the structure shown in FIG. 1 was manufactured. Specifically, an ITO electrode (first electrode) patterned in the shape as shown in Fig. 3 was formed on the first glass substrate. At this time, the pad portion of the first electrode was square, and the length of one side was 5 占 퐉 (width: 25 占 퐉 ² ), the length of the channel portion was 20 占 퐉, and the width was 2 占 퐉.

Then, silicon nitride was coated on the surface of the first glass substrate on which the ITO electrode was formed to form an insulating layer. On the other hand, molybdenum (Mo) was coated thinly on the second glass substrate so as to be transparent. Then, the first and second glass substrates were arranged so that the insulating layer of the first glass substrate and the electrode of the second glass substrate faced each other, and the edges excluding the injection hole were sealed. Next, a silicone oil in which TiO ₂ (average particle size: 0.2 탆) was dispersed in 0.01 wt% was injected into the injection port and the injection port was sealed to prepare a smart window.

Example  2: Smart Windows  Produce

A smart window was manufactured in the same manner as in Example 1 except that the length of one side of the pad portion of the first electrode was adjusted to 20 탆 (width: 400 탆 ² ) and the length of the channel portion was adjusted to 80 탆 in Example 1 .

Example  3: Smart Windows  Produce

A smart window was prepared in the same manner as in Example 1 except that TiO ₂ having an average particle diameter of 1.2 탆 was used in Example 1.

Example  4: Smart Windows  Produce

A smart window was manufactured in the same manner as in Example 3, except that the length of one side of the pad portion of the first electrode was adjusted to 20 탆 (width: 400 탆 ² ) and the length of the channel portion was adjusted to 80 탆 in Example 3 .

Example  5: Smart Windows  Produce

A smart window was prepared in the same manner as in Example 1 except that TiO ₂ having an average particle diameter of 7.4 탆 was used in Example 1.

Example  6: Smart Windows  Produce

In Example 5, a smart window was manufactured in the same manner as in Example 5, except that the length of one side of the pad portion of the first electrode was adjusted to 20 탆 (width: 400 탆 ² ) while the length of the channel portion was adjusted to 80 탆 .

Test Example : smart Windows  evaluation

A voltage (D.C.) was applied to the smart window prepared according to Examples 1 to 6 to measure the threshold voltage at which the smart window starts to be driven. Then, the response speed of the smart window and the light transmittance of the smart window in the driving state were measured and are shown in Table 1 below. The smart windows manufactured according to Examples 1 to 6 exhibited an average light transmittance of about 80% in the non-driven state.

Drive body
Average particle diameter [占 퐉] Length of one side of pad part [㎛]
(Width [탆 ² ]) Threshold voltage
[V] Response speed
[ms] Light transmittance
[%] Example 1 0.2 5 (25) 25 134 32 Example 2 0.2 20 (400) 20 86 24 Example 3 1.2 5 (25) 150 633 41 Example 4 1.2 20 (400) 150 236 40 Example 5 7.4 5 (25) 300 14531 56 Example 6 7.4 20 (400) 300 5695 48

Referring to Table 1, it can be seen that the smart window manufactured according to Examples 1 to 6 exhibits a high light transmittance in a non-driven state, but is transparent in a non-driven state, but becomes opaque due to low light transmittance when a voltage is applied thereto.

In particular, comparing Examples 2, 4 and 6, it can be seen that as the average particle diameter of the driving body is smaller, the threshold voltage is lower, the response speed is faster, and the light transmittance is lower, thereby realizing a more opaque state. Comparing Examples 1, 3 and 5 with Examples 2, 4 and 6, it can be seen that a faster response speed and a lower light transmittance can be expected as the width of the pad portion of the first electrode is larger.

11: first transparent substrate
12: second transparent substrate
21: first electrode
21a: pad portion
21b:
22: second electrode
31: Insulating layer
32: Fluid
41:

Claims (13)

A first transparent substrate;
A second transparent substrate disposed to face the first transparent substrate;
A first electrode formed on one surface of a first transparent substrate facing the second transparent substrate;
An insulating layer formed on a surface of the first electrode or a surface of the first transparent substrate on which the first electrode is formed and the first electrode;
A second electrode formed on one surface of the second transparent substrate facing the first transparent substrate;
A fluid filled between the insulating layer and the second electrode; And
And a drive body dispersed in the fluid in a non-driven state.
The smart window according to claim 1, wherein the first electrodes are patterned to have a plurality of pad portions spaced apart from each other and a plurality of channel portions connecting the pad portions.
The smart window of claim 1, wherein the first electrode and the second electrode are formed of a metal oxide or a metal.
The smart window according to claim 2, wherein the width of each pad portion in the first electrode is 1 占 퐉 ² to 250,000 占 퐉 ² .
3. The smart window of claim 2, wherein the first electrode is patterned such that the width of the channel portion is narrower than the widest width of the pad portion.
The smart window according to claim 2, wherein the width of the channel portion is 100 nm to 5 占 퐉.
The smart window according to claim 2, wherein the channel portion has a length of 1 탆 to 500 탆.
The smart window of claim 1, wherein the insulating layer is formed of silicon nitride, silicon oxide, or a mixture thereof.
The smart window of claim 1, wherein the fluid has a viscosity at 25 占 폚 of 10 to 5000 cP.
The smart window of claim 1, wherein the fluid is silicone oil.
The driving device according to claim 1, wherein the driving body comprises metal particles; Charged particles comprising a polymer and / or a metal oxide; Or carbon-based particles.
The smart window according to claim 1, wherein the driving body has an average particle diameter of 100 nm to 10 占 퐉.
The smart window according to claim 1, wherein at least part of the driving body dispersed in the fluid is agglomerated in the driving state of the smart window.

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