KR20150086892A - Smart windows for infrared cut - Google Patents

Abstract

The present invention relates to a smart window for blocking an infrared ray. More preferably, the present invention is to improve an energy saving effect by using a multi-layer metal film manufactured by depositing a metal thin film on the surface of polyester film with stable, transparent, and superior reflection characteristic by using a sputter method. The smart window comprises an ITO film layer (10) where an ITO layer (12) is attached to a side of an PET film layer (11), an Ag or Ag-alloy layer (20) which is attached to the ITO layer (11) of the ITO film layer (10), and a multi-layer metal film (40) which includes an ITO layer (30) attached to the upper side of the Ag or Ag-alloy layer (20).

Description

Smart windows for infrared cut}

The present invention relates to a smart window for infrared ray shielding, more preferably using a double-layer metal film produced by depositing a thin film on a surface of a polyester film through a sputtering method, So that the effect is also excellent.

In the polymer dispersed liquid crystal (PDLC) type light modulator, fine liquid crystal droplets are formed in a matrix of a polymer material, and in response to a voltage applied from the outside, when a voltage is applied (on state), liquid crystal is applied The liquid crystal is aligned along the direction of the electric field to coincide with the direction of the light passing through the light modulator to transmit the light, and when the voltage is not applied (off state), the liquid crystal is irregularly arranged, Because it is not arranged along the line, it will scatter light. That is, the PDLC type light adjuster can be driven in two states, that is, a state in which light is transmitted and a state in which light is scattered, depending on whether a voltage is applied or not.

Unlike other liquid crystal displays using nematic, such a PDLC type light adjuster has good brightness without using a polarizing plate, and a rubbing process for aligning liquid crystals can be omitted, so that the manufacturing process is simple and a device such as a window shielding film And can be applied to a display device having a large area.

Usually, a PDLC type light adjuster is formed by applying a liquid crystal dispersion composition containing a liquid crystal, an oligomer, a monomer, and a photoinitiator between two electrode base plates having an electrode layer to form a liquid crystal dispersion composition layer for producing a light adjuster, (Liquid droplets: liquid droplets, etc.) are formed between the matrix of polymeric materials by the photo-curing reaction of oligomers, monomers and the like due to the photoinitiator contained in the composition, Liquid crystal droplets are formed. Of course, the liquid crystal dispersion composition may not contain a photoinitiator if it induces curing by electron beams.

As an example of the prior art related to the PDLC type light adjuster, Japanese Patent Application Laid-open No. 10-2011-0062215 discloses a light modulating device comprising two transparent plate plates formed with transparent electrodes and a light modulating layer formed between two transparent plate plates, A PDLC type light adjuster having a pendulum hardness of 30 s or more measured after removing the transparent plate on one side of the transparent substrate is described.

In such prior art and other general PDLC type light adjusters, an electrode substrate plate made of ITO, which is a metal oxide film, has been widely used because of its excellent electric conductivity and transparency. More specifically, in the case of the ITO-deposited PET film used as the electrode substrate of the conventional PDLC type light adjuster, the sheet resistance of the ITO film for the touch panel is 100 to 270 Ω / □, the visible light transmittance is 88% The ITO film for ITO has a sheet resistance of 50 to 80 Ω / □ and a visible light transmittance of 80% or more. Of course, if the thickness of the ITO deposited film is increased, the electrical conductivity can be increased to several tens of ohms / square, but the visible light transmittance is reduced. In the case of an ITO-deposited PET film used as a transparent substrate of a PDLC type light modulator, it can be produced from a target containing 10 wt% of tin oxide (SnO 2) in indium oxide (InO 3).

Since the indium (In) of the ITO being used at this time is depleted of resources on earth's noble metal, the proportion of the cost of the PDLC-type light adjuster is increasing due to the increase of the cost over time, and a solution thereof is required . In addition, the PDLC type light modulator to which the ITO electrode substrate plate is applied transmits most of the infrared rays, and thus the heat ray shielding or absorbing function is insignificant. This is because when the PDLC type light adjuster is installed on the building, it can not selectively block the heat rays of the sunlight or control the transmission, so that the burden of the cooling cost in summer and the heating cost in winter can not be reduced. In particular, when the PDLC type light adjuster is applied to an automobile sunroof or the like, it is difficult to apply to automobiles due to high energy consumption for automobile cooling and heating because it does not have a function of blocking sunlight.

Thus, a polymeric dispersion stabilized light modulator using a nickel-based electrode as disclosed in Japanese Patent Laid-Open No. 10-2013-0107251 and a manufacturing method thereof have been disclosed.

The above structure uses a nickel-based alloy such as a Ni-alloy instead of a commonly used ITO film electrode, and has a low transmittance (about 60%) and a high sheet resistance (50 to 300 ohm). Therefore, it is difficult to limit the visibility of people and to block infrared rays to less than 30%.

And Patent Application No. 10-2010-0102392, as shown in Fig. 3, is a patent relating to an interlayer film, i.e., an adhesive sheet.

That is, by using an ITO film, it is possible to attach the release film to the PDLC film by using an optical acrylic adhesive having a transparency of 85% or more for the optical film, and it is unnecessary to replace the Smart Grass itself when replacement is required. It is easy to apply and removable, and there were many problems in blocking infrared rays.

1. Domestic Patent Publication No. 10-2013-0107251 2. Domestic Published Patent No. 10-2012-0045543 3. Domestic Patent Publication No. 10-2010-0102392 4. Domestic Patent Publication No. 10-2009-0020741

The present invention has been made to solve the above problems, and it is an electrode film for a low voltage driven PDLC that is designed by the construction, protection of the privacy of a vehicle, and the electrode film of PDLC which enters into the concept of light in a PDP. Even in the case of infrared ray shielding, the electrode film of the present invention is intended to cut off heat rays, that is, to reduce energy consumption by heating and cooling.

In addition, the metal electrode film according to the present invention is intended to have a high visible light transmittance of about 80% and a low surface resistance of about 1 to 10 ohms.

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.

An infrared shielding smart window 100 according to the present invention includes an ITO film layer 10 having an ITO layer 12 on one side of a PET film layer 11 and an ITO layer 12 of the ITO film layer 10, An Ag or Ag-alloy layer 20 attached to the substrate 11; And a multi-layer metal film 40 including an ITO layer 30 attached to the upper surface of the Ag or Ag-alloy layer 20.

In the present invention, the ITO layer layers 30 formed on the multi-layer metal film 40 are attached to each other with the LC + polymer 50 so that a multi-layer metal film 40 .

In the present invention, the ITO layer layer 12 has a thickness of 30 nm to 60 nm, the PET film layer 11 has a thickness of 25 um to 188 um, the Ag-alloy layer 20 has a thickness of 10 nm to 50 nm and the surface resistance is 1 to 10 ohm / sq. .

The present invention having such characteristics as described above has an effect that the visible light transmittance is 80% or more, and the near infrared ray transmittance is less than 30% without effectively limiting the visibility of the human being.

In addition, it has a high transmittance of 80% in the visible light region and a transmittance of less than 30% in the infrared region, and can reduce the infrared ray blocking effect by about 70%.

1A and 1B are structural diagrams of a PLDC showing a smart window according to the present invention.
2 is a graph showing an infrared ray blocking effect of a multi-layer metal film according to the present invention.
FIG. 3 is a stacked configuration of a smart window using a commonly used PDLC.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

 In the past, most of the techniques for adjusting the transmittance of solar light are mostly based on mounting a film having a specific transmittance on a window. However, since the glass produced in this way has no active control function for sunlight and is passive with selective shielding or transmission ability for a constant light wavelength region, there is a limit to meet the demand of the consumer. Therefore, There has been a growing need for glass that can control the transmissivity to the intestine.

Recently, as researches on thin films and liquid crystal materials having various functions have been rapidly developed, a new concept glass such as a smart window (transmissive variable glass, dimming glass) has been developed.

The smart window has the characteristic that when the electricity is not flowing, the glass is turned into a transparent state when the light is cut off and the electricity is flowed. In other words, when electricity is connected, it becomes transparent and a lot of light coming in through the window comes in. When the electricity is turned off, the window turns black or moody and the light is blocked. In this case, the time required to change the color takes about 1 / 1000th of a second to several minutes, and the light transmittance is usually 1 to 30%, which is significantly different from 40 to 80% of the transparent glass.

Smart windows that are currently being used include liquid crystal (LCD), electrochromic (EC), photochromic (PC), and suspended particle display (SPD). Polymers, The PDLC method using a polymer dispersed liquid crystal (PDLC) has a merit that the light transmission can be controlled without a polarizing film by using a refractive index difference between a liquid crystal and a polymer, and a large area can be manufactured.

In the case of the conventional PDLC type smart window, the transmittance can be freely adjusted by turning on / off the voltage. It is mainly used for housing, interior of house windows, living room, veranda, Fields and information display fields.

In addition, when the smart window is used as an automobile sunroof, it is possible to replace the curtain or the blind because it blocks the visible inertia by 40%, protects the driver's skin and eyes, and blocks more than 99% of ultraviolet rays.

However, it is difficult to block the infrared region with such a smart window, and there is a disadvantage that a separate heat ray shielding film must be attached in order to save energy for cooling and heating due to the insulation.

In order to compensate for these disadvantages, as shown in FIG. 3, it is desired to use a double-layer metal film capable of blocking infrared rays in place of the ITO film in the conventional PDLC type smart window construction.

In the conventional PDLC type smart window structure, an ITO film layer is formed on an upper surface of the glass layer and an ITO film layer is formed on the ITO film layer so that the ITO film layers are opposed to each other with an L / C polymer Layer structure.

The material of the metal and the metal oxide to be cut off the infrared rays is Ni, Cr, Al, Ag, ITO (TCO), SUS and the like. The thin film deposition uses a dry deposition technique using magnetron sputtering. The present invention can be a research technology motive differentiated from other wet processes.

That is, the thickness of the thin film is set to 10 to 50 nm. In the case of such a metal film, a thin film is deposited on the surface of the polyester film through a sputtering method, so that the coated metal can reflect a significant amount of the sunlight, thereby effectively controlling the solar control property.

Metals or metal oxides can be used to create a metallized type of film without visually reflecting the film. Various metals can be deposited on the film to control the wavelength of the IR region by adjusting the area of the solar light spectrum.

It is composed of a double layer metal film made by sputtering technique which is more stable and transparent and has a good reflection effect.

That is, the smart window for infrared ray blocking according to the present invention is configured such that infrared rays can be blocked with a transmittance of less than 30% by blocking the light when electricity is not flowing and turning the glass into a transparent state when electricity is flowed.

In order to manufacture the PDLC required for manufacturing the above-mentioned smart window, E7 (Merck Inc.) and NOA-65 (Nordland Products Co., Ltd.), which are the most commonly used cyanobiphenyl liquid crystal polymer matrix based on thiol- .) Is used.

The liquid crystal and the polymer matrix are mixed at a weight ratio of 1 to 1.5: 1, and a glass particle of several um is used as a spacer to mix the mixture.

After uniformly applying the mixture on one ITO electrode, a piece of ITO electrode is further placed on the ITO electrode. After the ITO electrode is laminated, ultraviolet rays (UV) are irradiated to activate the liquid crystal.

At this time, in the present invention, a metal film based on an ag-alloy is substituted for the ITO.

1A, the smart window 100 includes an ITO film layer 10 having an ITO layer 12 adhered on one side of a PET film layer 11, as shown in FIG. 1A, ). An Ag or Ag-alloy layer 20 is attached to the ITO layer 12 of the ITO film layer 10 and an ITO layer 30 is formed on the Ag or Ag- To form a multi-layer metal film (40).

1B, the ITO layer 30 formed on the multi-layer metal film 40 is attached to the LC + polymer 50 so as to face each other, and a multi-layer metal film (40) constitute a multi-layered structure.

In this case, the ITO layer layer is 30 to 60 nm, the PET film layer is 25 to 188 nm, the Ag-alloy layer is 10 to 50 nm, and the sheet resistance is 1 to 10 ohm / sq.

Therefore, the present invention is advantageous for driving a low-voltage PDLC (vehicle) with a significantly lower resistance than an ITO film layer.

The infrared ray shielding effect of the multi-layer metal film 40 constructed as described above is shown in FIG.

That is, in the case of the ITO single layer, the infrared ray (950 nm or more) region can not be blocked. However, when a multi-layer structure such as ITO / Ag / ITO is designed, it is possible to effectively block the infrared (950 nm or more) region while maintaining the transmittance of visible light (550 nm, 400 to 700 nm).

As described above, the metal electrode film according to the present invention has a high visible light transmittance of about 80% and a low surface resistance of about 1 to 10 ohm.

As shown in Table 1 below, the transmittance of the infrared screening smart window is as follows. In the case of No. 6 and No. 7, the visible light transmittance is 80% or more and the near infrared ray transmittance is less than 30% Energy can be blocked.

thickness VLT
(%, 550 nm) NIRT
(%, 950 nm) Remarks ITO (nm) Ag-alloy (nm) One 30 10 66.8 51.2 2 30 20 77.3 52.8 3 30 40 70.8 26.3 5 45 40 78.9 28.1 6 50 40 81.4 28.8 7 60 40 82.1 29.9

- VLT: Visible light transmittance, transmittance at a wavelength of 550nm, visible light region, directly affecting human vision.

- NIRT: near infrared ray transmittance, transmittance at 950nm wavelength, near infrared ray area between visible light region and infrared ray region, and does not affect human vision.

Although the present invention having been described above has been described with reference to a limited number of embodiments, it is to be understood that the present invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the present invention by those skilled in the art. Various modifications and variations are possible within the scope of the appended claims.

10. ITO film layer 11. PET film layer
12. ITO Layer layer 20. Ag or Ag-alloy layer
30. ITO Layer Layer 40. Multi-Layer Metal Film
50. LC + polymer

Claims (3)

An ITO film layer 10 having an ITO layer 12 on one side of the PET film layer 11,
An Ag or Ag-alloy layer 20 attached to the ITO layer 11 of the ITO film layer 10,
And a multi-layer metal film (40) including an ITO layer (30) attached to the upper surface of the Ag or Ag-alloy layer (20). The method according to claim 1,
Layered metal film 40 is formed by attaching the ITO layer 30 formed on the multi-layered metal film 40 with the LC + polymer 50 facing each other. Smart windows for blocking. The method according to claim 1,
Wherein the ITO layer layer 12 has a thickness of 30 to 60 nm, the PET film layer 11 has a thickness of 25 to 188 nm, the Ag-alloy layer 20 has a thickness of 10 to 50 nm, and the sheet resistance has 1 to 10 ohm / sq. Smart for Windows.

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