KR102675159B1 - Smart windows - Google Patents

Abstract

The present invention relates to a first glass plate; a transmittance variable layer formed on the first glass plate and containing an inorganic material; a second glass plate formed on the transmittance variable layer; and an anti-reflection layer formed on the second glass plate, wherein the transmittance variable layer is in contact with the first electrode and the second electrode.

Description

SMART WINDOWS

The present invention relates to a smart window with excellent durability and adjustable light transmittance.

Recently, there has been an increasing number of cases of applying functional films to architectural or vehicle glass to freely adjust the transmittance of sunlight flowing in from the outside, thereby reducing energy loss and improving energy efficiency, thereby providing a comfortable environment for users. These functional films lower the transmittance of sunlight, preventing external heat from flowing into the building, and increase the transmittance of sunlight, improving the sense of openness and allowing external heat to flow into the building.

Such variable transmittance films typically contain organic materials and are of the supported particle device (SPD) or polymer dispersed liquid crystal (PDLC) type. In addition, variable transmittance films typically electrically adjust the transmittance of sunlight depending on the orientation of the organic polymer material. For example, Korean Patent Publication No. 2005-0089380 (Patent Document 1) includes a first glass plate (1), one or more polymer layers (2), and a polymer matrix (9) in which liquid crystal droplets (8) are embedded. A vehicle window glass is disclosed comprising a PDLC layer (4), one or more polymer layers (6), and a second pane (7) in this order. However, the transmittance variable film using an organic material, such as the vehicle window glass of Patent Document 1, has a problem in that the structure of the organic polymer material may be modified by ultraviolet or infrared rays in sunlight, which leads to a decrease in the transmittance control ability, which is the main performance. .

Therefore, there is a need for research and development on smart windows that have excellent durability and do not cause problems such as a decrease in transmittance control ability even when exposed to harsh environments for a long period of time, and that allow easy control of light transmittance.

Korean Patent Publication No. 2005-0089380 (Publication date: 2020.2.19.)

Accordingly, the present invention seeks to provide a smart window that has excellent durability and does not suffer from problems such as a decrease in transmittance control ability even when exposed to a cold environment for a long period of time, and that allows easy control of light transmittance.

The present invention relates to a first glass plate;

a transmittance variable layer formed on the first glass plate and containing an inorganic material;

a second glass plate formed on the transmittance variable layer; and

It includes an anti-reflection layer formed on the second glass plate,

The transmittance variable layer is in contact with the first electrode and the second electrode and provides a smart window.

The smart window according to the present invention has excellent durability, so even when exposed to a harsh environment for a long period of time, problems such as a decrease in transmittance control do not occur, and light transmittance can be easily adjusted. For this reason, the smart window is very suitable as a material for various fields such as construction materials for residential and non-residential buildings, and vehicles.

1 and 2 are cross-sectional views of a smart window according to an embodiment of the present invention.
Figure 3 is a cross-sectional view of a transmittance variable layer according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

In the present invention, when a member is said to be located “on” another member, this includes not only the case where a member is in contact with another member, but also the case where another member exists between the two members.

The smart window according to the present invention includes a first glass plate, a transmittance variable layer containing an inorganic material, a second glass plate, and an anti-reflection layer. Referring to FIG. 1, the smart window 10 has a form in which a first glass plate 100, a transmittance variable layer 200 containing an inorganic material, a second glass plate 300, and an anti-reflection layer 400 are stacked in that order. It can be included. As described above, the smart window according to the present invention includes a variable transmittance layer containing inorganic materials instead of organic materials whose structure is modified by sunlight, and has excellent durability against sunlight, allowing the transmittance to be adjusted even when exposed to a harsh environment for a long period of time. It has the advantage of not causing problems such as degradation.

First glass plate and second glass plate

As the first glass plate, ordinary glass such as soda lime glass used for construction or automobiles can be used.

Additionally, each of the first and second glass plates may be made of glass with an appropriate thickness depending on the purpose of use. For example, the first glass plate and the second glass plate may each independently have an average thickness of 1.0 to 2.5 mm, or 1.0 to 2.1 mm. If the average thickness of the first glass plate and the second glass plate is less than the above range, there is a risk of damage because the manufactured window is vulnerable to external shock, and if it exceeds the above range, the weight of the manufactured window becomes heavy and includes this. Problems may arise that result in a decrease in fuel efficiency of vehicles, etc.

The first glass plate and the second glass plate may each independently additionally include a dye coating layer. At this time, the dye coating layer may be formed on the surface of the first glass plate in contact with the transmittance variable layer, and may be formed on the surface of the second glass plate in contact with the anti-reflection layer. The dye coating layer can be used without particular limitation as long as it is a dye that can be commonly applied to a glass plate, and may include, for example, a black inorganic dye.

Transmittance variable layer

The variable transmittance layer controls the transmittance of sunlight to reduce energy loss and improve energy efficiency.

The transmittance variable layer may include a P-type semiconductor and an N-type semiconductor. When the transmittance variable layer includes a P-type semiconductor and an N-type semiconductor, it has the effect of confining charges within the energy band gap of the layer having semiconductor properties, thereby controlling light transmittance.

At this time, the transmittance variable layer may include a material having a bandgap energy of 1.0 to 5.0 eV, or 1.5 to 4.5 eV. That is, the bandgap energy of the P-type semiconductor and N-type semiconductor included in the transmittance variable layer may be within the above range. If the bandgap energy of the P-type semiconductor and N-type semiconductor in the transmittance variable layer is less than the above range, the transmittance variable range may become smaller, and if it exceeds the above range, a high operating voltage is required or the transmittance variable layer may be due to a high operating voltage. The negative effects may accumulate and limit repetitive motion.

The transmittance variable layer may include a base layer, a first electrode layer, an insulating layer, a first functional layer, a barrier layer, a second functional layer, and a second electrode layer stacked in that order (see FIG. 3).

Additionally, the transmittance variable layer may have an average thickness of 25 to 180 ㎛, or 50 to 150 ㎛, and in this case, the average thickness of the transmittance variable layer may be the thickness excluding the base layer. If the average thickness of the transmittance variable layer is less than the above range, the transmittance variable range may be reduced, or the thickness of the transmittance variable layer may be so thin that current may not operate through it directly, and if it exceeds the above range, a high operating voltage may be required, or Even if the operating voltage is increased, the movement of charge is limited and the function may not be displayed.

The base layer is a transparent material that can be used without particular restrictions as long as it is a commonly used material, and examples include polyethylene terephthalate (PET) and glass. Additionally, the base layer may have an average thickness of 5㎛ to 10mm, or 300㎛ to 6mm. If the average thickness of the base layer is less than the above range, a problem may occur in which it is difficult to support the transmittance variable layer due to the thin thickness of the base layer, and if it exceeds the above range, a problem may occur in which the transmittance of the transmittance variable layer is lowered. .

The first electrode layer and the second electrode layer serve to apply current to the variable transmittance layer. At this time, the first electrode layer and the second electrode layer may include transparent conductive oxide or conductive nanoparticles, for example, tin-doped indium oxide (ITO), antimony-doped or fluorine-doped tin oxide (SnO ₂ :F) or transparent conductive oxides such as aluminum-doped zinc oxide (ZnO:Al), conductive nanoparticles such as silver nanowires, and conductive polymers. Additionally, the first electrode layer and the second electrode layer may each independently have an average thickness of 10 to 800 nm. Specifically, the first electrode layer may have an average thickness of 20 to 800 nm or 50 to 500 nm, and the second electrode layer may have an average thickness of 20 to 800 nm or 50 to 200 nm. If the average thickness of the first electrode layer and the second electrode layer is less than the above range, the surface resistance of the transmittance variable layer increases, making it difficult to obtain uniform transmittance, and if it exceeds the above range, cracks may occur in the electrode during the process. Problems may occur or the permeability may decrease.

The insulating layer serves to maintain transmittance even when no voltage is applied. At this time, the insulating layer may include any material that can be commonly used for interlayer insulation without particular limitation, for example, titanium dioxide (TiO ₂ ), niobium oxide (Nb ₂ O ₅ ), aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), silicon nitride (SiN), etc. Additionally, the insulating layer may have an average thickness of 10 to 200 nm, or 30 to 200 nm. If the average thickness of the insulating layer is less than the above range, the variable transmission function deteriorates through direct current passage due to defects such as pinholes, and the charge contained in the functional layer to which no voltage is applied leaks, thereby reducing the permeability in the state of not applying voltage. There is a problem in that it is difficult to maintain, and if it exceeds the above range, a problem may occur in which it does not operate even if a high voltage is applied due to the thick thickness of the insulating layer.

Each of the first functional layer and the second functional layer may include a P-type semiconductor or an N-type semiconductor. Specifically, one of the first functional layer and the second functional layer may include a P-type semiconductor, and the other may include an N-type semiconductor.

At this time, the P-type semiconductor can be used without particular limitation as long as it is commonly used, and examples include oxides of metals selected from the group consisting of W and Ni.

In addition, the N-type semiconductor may be used without particular limitation as long as it is commonly used, for example, oxides of metals selected from the group consisting of Sn, Ti, Zn, In, Sb, and Cd. You can.

The first functional layer and the second functional layer may each independently have an average thickness of 10 to 300 nm, 20 to 300 nm, or 20 to 100 nm. If the average thickness of the first functional layer and the second functional layer is less than the above range, the performance of the transmittance variable layer may deteriorate, and if it exceeds the above range, the operating reaction time may be long.

The barrier layer can be used without particular limitation as long as it is generally sandwiched between a P-type semiconductor and an N-type semiconductor, for example, silica (SiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), zirconia (ZrO), and alumina. (Al ₂ O ₃ ), nickel oxide (NiO), etc., and there is no particular limitation as long as it is a material that produces defects when irradiated with ultraviolet rays (UV). Additionally, the barrier layer may have an average thickness of 1 to 150 nm, or 10 to 100 nm.

If the average thickness of the barrier layer is less than the above range, injection of charge into the first functional layer and the second functional layer may be limited, and if it exceeds the above range, it may exhibit insulating properties and a problem requiring a high operating voltage may occur. You can.

The transmittance variable layer as described above may be formed by laminating a first electrode layer, an insulating layer, a first functional layer, a barrier layer, a second functional layer, and a second electrode layer on a base layer by sputtering, but is not limited thereto.

Anti-reflection layer

The anti-reflection layer serves to provide high shielding performance of the manufactured window by reflecting sunlight and at the same time realize low radiation.

The anti-reflection layer may include a metal with excellent conductivity, such as nickel (Ni), nickel-chromium (Ni-Cr) alloy, SiAl alloy, ZnAl alloy, zirconium (Zr), nitrides thereof, oxides thereof, and It may contain one type selected from the group consisting of these nitride oxides. Specifically, the anti-reflection layer may include one or more selected from the group consisting of Zr, SiAlN, SiAlN ₂ , ZnAlO, and NiCrO.

Additionally, the average thickness of the anti-reflection layer may be 120 to 250 nm or 140 to 210 nm. If the thickness of the anti-reflection layer is less than the above range, the anti-reflection layer is not formed properly, causing a problem of insufficient low-emissivity performance of the manufactured glass, and if it exceeds the above range, the reflectance of the manufactured glass increases, thereby increasing the color of the glass surface. This deterioration problem can be prevented.

The smart window may additionally include an adhesive layer.

adhesive layer

Specifically, the smart window may further include a first adhesive layer between the first glass plate and the transmittance variable layer, and may further include a second adhesive layer between the transmittance variable layer and the second glass plate. Referring to FIG. 2, the smart window 10 includes a first glass plate 100, a first adhesive layer 510, a transmittance variable layer 200 containing an inorganic material, a second adhesive layer 520, and a second glass plate 300. ) and an anti-reflection layer 400 may be sequentially stacked.

The first adhesive layer and the second adhesive layer may each independently include one or more selected from the group consisting of polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), and thermoplastic polyurethane (TPU).

Additionally, the first adhesive layer and the second adhesive layer may each independently have an average thickness of 0.2 to 1.0 ㎛ or 0.3 to 0.8 ㎛. If the average thickness of the first adhesive layer and the second adhesive layer is less than the above range, bubbles may be generated during bonding due to the step with the variable transmittance layer, or the film may be easily torn and difficult to handle due to the low thickness during the bonding process, increasing process time. Alternatively, it may be vulnerable to external shock after bonding, causing the glass and film to penetrate. In addition, when the average thickness of the first adhesive layer and the second adhesive layer exceeds the above range, the hardness of the film must be lowered by introducing an additional process in the bonding process due to the hardness of the adhesive layer, or the hardness of the smart window manufactured due to the thickness of the adhesive layer must be lowered. As the weight increases, problems that increase vehicle fuel efficiency may occur.

Specifically, the first adhesive layer may have an average thickness of 0.5 to 1.0 ㎛ or 0.7 to 0.8 ㎛, and the second adhesive layer may have an average thickness of 0.2 to 0.5 ㎛ or 0.3 to 0.4 ㎛. When the average thickness of the first adhesive layer and the second adhesive layer is within the above range, the transmittance variable layer and the glass plate can be effectively bonded to the thinnest possible, and the level difference due to the thickness difference with the transmittance variable layer can be appropriately compensated.

The smart window according to the present invention may have a visible light transmittance of 60 to 80% or 70 to 75% when current is applied, and the visible light transmittance when no current is applied may be more than 0% and less than 5%.

In addition, the smart window may have a thermal energy transmittance of more than 40% and 50% or less when electric current is applied, and a total thermal energy transmittance of 5 to 15% when electric current is not applied.

As described above, the smart window according to the present invention has excellent durability, so even when exposed to a harsh environment for a long period of time, problems such as a decrease in transmittance control do not occur, and light transmittance can be easily adjusted. For this reason, the smart window is very suitable as a material for various fields such as construction materials for residential and non-residential buildings, and vehicles.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited to these examples in any way.

[Example]

Example 1.

1-1: Preparation of variable transmittance layer

An ITO layer (first electrode layer) with a thickness of 150 nm was formed on a PET film (base layer) with a thickness of 120 μm by roll-to-roll sputtering, and then cut into pieces of 100 mm x 100 mm. Afterwards, it was cleaned with an ultrasonic cleaner in the order of acetone, methanol, and ultrapure water (D.I. water) for 10 minutes each without intermediate drying, and then dried for 20 minutes using a hotplate at 120°C.

Afterwards, TiO ₂ was deposited to a thickness of 50 nm using RF sputtering to form an insulating layer. At this time, one corner was masked so that the electrode could be directly connected to the ITO layer (first electrode layer) after completion. The RT sputter process created a vacuum of 8.0Х10 ^-6 Torr and then injected high purity (99.999%) argon gas (Ar) (99.999%) to form a process pressure of 5Х10 ^-3 Torr. Afterwards, pre-sputtering was performed for 10 minutes at an output of 100 W, and then sputtering was performed for 15 minutes at an output of 200 W. At this time, in order to ensure thickness uniformity, the base layer on which the first electrode layer was formed was rotated at a speed of 10 rpm.

Afterwards, the surface was treated with a UV-Ozone processor for 5 minutes, and then a SnO ₂ solution was spin-coated to form the first functional layer (N-type semiconductor). The SnO ₂ solution was prepared by mixing 0.75 g of SnO ₂ (Sigma Aldrich), 2.56 g of xylene (Sigma Aldrich), and 0.1 g of silicone oil with an insulating effect (Si-oil, manufactured by Isung Materials) at 1000 rpm using a steer bar. It was prepared by mixing for 20 minutes. Specifically, the first functional layer was spin-coated with a SnO ₂ solution at 2000 rpm for 8 seconds and then dried on a hotplate at 80°C for 10 minutes. Afterwards, the surface of the first functional layer was treated using UV-Ozone equipment with an output of 35 mW for 20 minutes.

The silicone oil contained in the coating solution of the first functional layer undergoes phase separation when the first functional layer is coated and dried to form a SnO ₂ /SiO layer. In other words, phase separation of silicon and Sn was induced and a multi-layer first functional layer was obtained with one coating. Therefore, a SiO layer as a barrier layer was formed on the surface of the SnO ₂ layer as the first functional layer.

After UV treatment, the NiO solution was spin coated using the same spin coating process as the first functional layer to form a second functional layer (P-type semiconductor). Afterwards, it was dried on a hot plate at 115°C for 10 minutes.

Afterwards, in order to deposit the ITO layer, which is the second electrode layer, the area where the electrode would be attached was masked, and the ITO layer was deposited to a thickness of about 100 nm using DC sputtering. The ITO target was composed of In ₂ O ₃ and SnO ₂ at a mass ratio of 90:10, and had a diameter of 3 inches and a thickness of 1/4 inch. Specifically, for deposition, a vacuum of 8.0x10 ^-6 Torr was created and high purity (99.999%) argon gas (Ar) was injected to form a process pressure of 5Х10 ^-3 Torr. Afterwards, pre-sputtering was performed for 10 minutes at an output of 50W, the process pressure was lowered to 2Х10 ^-3 Torr, and ITO was deposited for 7 minutes at the same output. At this time, to ensure thickness uniformity, the substrate was rotated at 10 rpm and cooled down for 5 minutes after the sputtering process was completed.

1-2: Manufacturing of smart windows

A first adhesive layer with a thickness of 0.76 mm was formed on a transparent glass substrate (first glass plate) with a thickness of 2.1 mm using ethylene-vinyl acetate (PVB, manufacturer: Sekisui, product name: S-LEK). Thereafter, the transmittance variable layer of Example 1-1 was laminated on the first adhesive layer, and a 0.38 mm thick layer was formed on the transmittance variable layer using ethylene-vinyl acetate (PVB, manufacturer: Sekisui, product name: S-LEK). 2 An adhesive layer was formed.

SiAl, ZnAl, NiCr, and Zr targets were sequentially laminated on a 2.1 mm thick transparent glass substrate (second glass plate) by sputtering under a nitrogen and argon atmosphere to form an anti-reflection layer with a total thickness of 150 nm.

Afterwards, a smart window was manufactured by stacking a second glass plate with an anti-reflection layer formed on the second adhesive layer so that the general glass surface, not the anti-reflection layer, was in contact with the second adhesive layer.

Examples 2 to 6.

A smart window was manufactured in the same manner as Example 1, except that the thickness of each layer of the transmittance variable layer was adjusted as shown in Table 1.

(Thickness: nm) first electrode layer insulating layer first functional layer barrier layer second functional layer second electrode layer Example 1 150 50 60 40 70 100 Example 2 150 50 40 40 40 100 Example 3 150 50 20 40 70 100 Example 4 150 50 100 40 70 100 Example 5 150 50 60 40 20 100 Example 6 150 50 60 40 100 100

Examples 7 to 10 and Comparative Example 1.

A smart window was manufactured in the same manner as Example 1, except that the thickness of each layer was adjusted as shown in Table 2.

(thickness) 1st glass plate (mm) First adhesive layer (mm) Transmittance variable layer (nm) Second adhesive layer (mm) 2nd glass plate (mm) Anti-reflection layer (nm) Example 1 2.1 0.76 470 0.38 2.1 150 Example 7 3.0 0.76 470 0.38 2.1 150 Example 8 2.1 0.38 470 0.38 2.1 150 Example 9 2.1 0.76 470 0.38 1.6 150 Example 10 2.1 0.76 470 0.38 3.0 150 Comparative Example 1 2.1 0.76 470 0.38 2.1 -

Comparative Example 2.

A smart window was manufactured in the same manner as Example 1-2, except that Gauzy's LCG was used as a supended particle device (SPD) film instead of the transmittance variable layer.

Comparative Example 3.

A smart window was manufactured in the same manner as Example 1-2, except that Livicon's Normal film was used as a polymer dispersed liquid crystal (PDLC) film instead of the transmittance variable layer.

Test example: Characteristic evaluation

The physical properties of the smart windows manufactured in Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 3.

(1) Visible light transmittance, thermal energy transmittance, visible light reflectance, and energy reflectance

As a measuring instrument, a spectraphotometer carry 5000 from Agilent technologies was used, and transmittance and reflectance were measured in the spectrum of visible light range (380 to 780 nm), ultraviolet rays (300 to 400 nm), and solar heat rays (thermal energy, 300 to 2500 nm). , the total energy transmittance was calculated according to the KS L 2514 standard.

(2) Weather resistance: gray scale and colorimetry

An energy of 2,500 kJ/m ² was irradiated using a xenon weatherometer tester according to the method described in SAE J 2527, and a total of 4 cycles were processed (taking 158 days). Afterwards, gray scale and color difference (ΔE) were measured.

division Visible light transmittance (%) Thermal energy transmittance (%) Visible light reflectance (%) Energy reflectance (%) Total energy transmittance (%) weather resistance gray scale color difference Example 1 73.25 43.91 18.41 16.52 53.89 4 1.012 Example 2 71.76 42.34 16.55 15.94 54.26 4 1.124 Example 3 72.87 43.86 17.49 16.29 55.35 4 1.158 Example 4 72.19 44.69 18.32 14.96 54.84 4 1.241 Example 5 72.55 43.72 17.64 15.88 53.71 4 1.352 Example 6 71.93 44.41 16.99 15.46 53.28 4 1.185 Example 7 72.14 43.23 17.58 16.14 54.33 4 1.241 Example 8 71.87 46.27 14.67 13.89 54.71 4 1.452 Example 9 72.37 48.18 15.78 15.29 54.82 4 1.229 Example 10 73.59 49.58 16.58 14.28 55.54 4 1.318 Comparative Example 1 68.15 50.48 17.55 13.22 75.22 6 2.584 Comparative Example 2 29.68 40.68 7.49 7.31 54.87 7 4.351 Comparative Example 3 76.19 64.90 12.87 10.02 71.74 6 5.479

As shown in Table 3, the smart windows of Examples 1 to 10 had appropriate visible light transmittance, thermal energy transmittance, visible light reflectance, and energy reflectance, and had excellent weather resistance.

On the other hand, Comparative Example 1, which did not include an anti-reflection layer, had a high total energy transmittance and a high gray scale due to insufficient weather resistance.

In addition, Comparative Example 2, which included an SPD film instead of a variable transmittance layer, had insufficient visible light transmittance, visible light reflectance, and energy reflectance, and had large gray scale and color difference due to insufficient weather resistance.

Comparative Example 3, which included a PDLC film instead of a variable transmittance layer, had high thermal energy transmittance and total energy transmittance, and had large gray scale and color difference due to insufficient weather resistance.

Claims (6)

first glass plate;
a transmittance variable layer formed on the first glass plate and containing an inorganic material;
a second glass plate formed on the transmittance variable layer; and
It includes an anti-reflection layer formed on the second glass plate,
The transmittance variable layer is in contact with the first electrode and the second electrode,
The antireflection layer is one selected from the group consisting of nickel (Ni), nickel-chromium (Ni-Cr) alloy, SiAl alloy, ZnAl alloy, zirconium (Zr), their nitrides, their oxides, and their nitride oxides. Includes,
When current is applied, the visible light transmittance is 60 to 80%, the heat energy transmittance is between 40% and 50%, and when no current is applied, the visible light transmittance is between 0% and 5% or less, and the heat energy transmittance is 5% to 15%. , smart windows. In claim 1,
A smart window wherein the transmittance variable layer includes a P-type semiconductor and an N-type semiconductor and has an average thickness of 25 to 180 ㎛. In claim 2,
A smart window, wherein the transmittance variable layer includes a material having a bandgap energy of 1.0 to 5.0 eV. In claim 1,
The transmittance variable layer is a smart window including a base layer, a first electrode layer, an insulating layer, a first functional layer, a barrier layer, a second functional layer, and a second electrode layer stacked in that order. In claim 4,
A smart window, wherein one of the first functional layer and the second functional layer includes a P-type semiconductor, and the other includes an N-type semiconductor. In claim 4,
The first electrode layer has an average thickness of 20 to 800 nm,
The insulating layer has an average thickness of 10 to 200 nm,
The first functional layer has an average thickness of 10 to 300 nm,
The barrier layer has an average thickness of 1 to 150 nm,
The second functional layer has an average thickness of 10 to 300 nm,
The second electrode layer has an average thickness of 20 to 800 nm.