KR20220159092A - Blind slats and blind comprising the same - Google Patents

Abstract

The present invention relates to a blind slat and a blind including the same. The blind slat according to the present invention has a structure in which transparent outer and inner plates, connecting rods, and a plurality of supports are integrally formed, wherein the transparent outer and inner plates have a thermal insulation layer and extend in a longitudinal direction while spaced apart from each other to form a dead-air layer, the connecting rods are formed in the longitudinal direction at upper and lower ends of the outer and inner plates, and the plurality of supports are placed between the outer and inner plates. The blind slat and the blind including the same according to the present invention exhibit complex effects of shading, heat blocking, and lighting to effectively block radiant heat through shading of direct solar radiation, thereby reducing cooling energy in summer and heating heat loss in winter. The blind slat and the blind can reduce cooling and heating energy and lighting energy at the same time by harmonizing a shielding coefficient and a visible light transmittance rate resulting from heat blocking to create a comfortable indoor environment through balanced natural light and reduced glare. Meanwhile, the blind slat and the blind can exhibit good lighting properties by letting a significant portion of visible rays pass while effectively blocking infrared rays and ultraviolet rays, and thus can save lighting energy. Moreover, the blind slat and the blind have no thermal deformation caused by solar radiation, are lightweight, have high structural rigidity, and have excellent heat-blocking effects by the air layer.

Description

Blind slats and blinds including them {BLIND SLATS AND BLIND COMPRISING THE SAME}

The present invention relates to a blind slat and a blind including the same, and more specifically, to lower a shading coefficient (Sc, Reduction Factor of Shading Coefficient) by using a heat-blocking metal oxide and simultaneously transmit visible light for saving lighting energy. By using a polymer and including a high-insulation air layer for heat shielding, it exhibits a complex effect of shading, heat shielding, and lighting to effectively block radiant heat through shielding of direct solar radiation, reducing cooling energy in summer and heating heat loss in winter while enabling natural light It relates to a lightweight translucent blind slat without thermal deformation that can create a comfortable indoor environment by reducing the brightness and brightness, and a blind including the same.

In recent years, due to the depletion of fossil fuels and frequent abnormal climates worldwide, response to climate change caused by greenhouse gases and energy saving and efficiency improvement are global issues, which require a new philosophy and paradigm to realize a low-carbon society and civilization.

Korea is one of the world’s top 10 energy consuming countries, and its total energy consumption is continuously increasing. Its carbon dioxide emissions rank _first among OECD (Organization for Economic Cooperation and Development) countries in the rate of increase in CO2 emissions since 1990, and rank 7th in the world in total emissions since 2011. Above, we are aiming for 2050 carbon neutrality by reducing greenhouse gases.

With the vision of realizing a green advanced country through the vitalization of green buildings in the field of architecture, Korea enacts relevant laws and implements policy revitalization measures to reduce energy consumption and greenhouse gas emissions step by step, and as part of vitalizing green buildings, building energy efficiency Various eco ^- friendly certification systems including grade certification, building energy consumption total amount system and new and renewable energy mandatory quota system are being implemented. Mandatory zero-energy buildings.

In order to save energy in existing old buildings, replacement of heating and cooling equipment with high-efficiency energy equipment, insulation reinforcement, replacement with high-efficiency windows and doors, and the use of renewable energy can be considered, but all of these require significant investment.

Therefore, it is possible to consider installing a shading system on windows as a way to quickly and easily obtain insulation and energy saving effects for existing buildings at the lowest cost, but in the shading system, the shading coefficient (SC) and solar radiation Solar Heat Gain Coefficient (SHGC) is a factor that affects heating and cooling load, and Visible Light Transmittance (VLT) is a factor that affects indoor lighting load. There is a problem in that it is difficult to overcome an offset effect due to a mutually contradictory trade-off relationship between heating and cooling energy saving and lighting energy increase by blocking light energy.

In general, natural lighting is defined as accepting sunlight so as not to interfere with human vision by using natural light through windows, and its ultimate purpose is to make the indoor environment of a building comfortable through the appropriate inflow of daylight. In terms of natural light, it is important to create a comfortable indoor environment by reducing glazing and uniformity inside the building, rather than simply using external natural light through windows.

In general, glass used for windows and doors has high visible light transmittance, so indoor lighting energy can be reduced through natural light by appropriate inflow of sunlight, but solar radiation caused by direct, diffused, and reflected rays through windows and doors is harmful to the indoor environment. This causes a greenhouse effect, which affects the energy consumption of air-conditioning and heating devices, resulting in an increase in cooling costs.

Therefore, awnings have been widely used as a mechanism for creating a comfortable indoor environment by reducing the cooling and heating load of the room by appropriately inflowing or blocking solar radiation from the outside and inducing natural light.

There are many types of awnings for solar radiation control, and depending on their shape, installation location, and control method, they have the effect of improving visual comfort, contributing to energy savings, and enhancing the image of architecture.

In addition, awnings reduce cooling energy and enable natural lighting by controlling direct solar radiation in the summer season, thereby reducing energy consumption for heating and cooling the building, although it varies depending on the shape, control method, and location, and the shielding factor depending on the shape and installation location also vary widely.

Examples of such types of awnings include louvers, blinds, light shelves, and awnings, but louvers, light shelves, and awnings are installed outdoors, so only blinds will be mentioned. do.

Blinds are generally installed in various shapes and positions inside a building, and include Roman blinds, Austrian blinds, Venetian blinds, roller blinds, vertical blinds, and the like.

Roman blinds are in the form of raising and lowering wide pleats in the vertical direction by inserting rods or cords made of aluminum, PVC, or wood in the horizontal direction. Venetian blinds are narrower and thinner than louver blades, and they are blinds that block sunlight by weaving and hanging slats made of metal, wood, or plastic plates at regular intervals. There is a separate string to adjust the inclination of the blind and a string to raise the whole, so it is possible to adjust the inclination of the plate according to the angle of the light beam or to raise the entire blind.

Venetian blinds are internal Venetian blinds (IVB) installed inside the windows of a building and mechanically operated intermediate Venetian blinds installed between double skin facades or double-glazed windows. There are Venetian blinds (IMVB) and External Venetian blinds (EVB) with excellent thermal insulation installed outside the windows of buildings, but most of them are IVB.

Roll blinds (roller blinds) are often referred to as roll screens, and are often used when several wide windows are connected. As a type of awning in which the screen is rolled up and down when a string is pulled, it is currently widely used in Korea.

Vertical blinds, which are often used instead of curtains, use vertical slats, and connect a plurality of fabric or resin slats in the vertical direction so that they can be tilted with a string. It is a form that allows you to control the amount of inflow and ventilation.

Since most conventional blinds have a main purpose of blocking light, the material itself is made of an opaque material, so when the blind is applied, the external view is completely blocked from the view, resulting in the blocking of light, and the blind is partially adjusted for lighting. In this case, there is a problem in that it is not easy to create a comfortable indoor environment by reducing the amount of bacteria and brightness in the room because the natural light from outside is directly introduced into the gap.

Conventional Patent Registration No. 1236332 (registered on February 18, 2013) is a slat body with an insertion groove formed in the longitudinal direction, a multi-faceted blade positioned outside the slat body and formed with a multi-faceted angle to reflect sunlight to the outside or inside, It includes a heat insulating material inserted into the insertion groove, and the multi-faceted blade is formed in a triangular shape with a horizontal top and a narrower width toward the bottom, and is fitted into the fitting part of the slat body in a sliding manner Light, characterized in that Blind slats with reflective angles and insulation are proposed, but this is only about light blocking and heat blocking by morphological factors, and is different from simultaneous savings in cooling and heating energy and lighting energy by harmonizing the shielding coefficient by heat blocking and visible light transmittance. There is a distance.

In addition, Patent Registration No. 1758919 (registered on October 2, 2017) discloses a visor slat capable of reflecting sunlight coming from the outside in a retroreflective form, and a lighting slat that steers sunlight coming from the outside to the interior ceiling of the room. Including, we propose a blind that is disposed so that the light slat is positioned above the awning slat, and the lighting and blocking are performed by adjusting the inclination angle of the awning slat and the light shading slat having a corrugated structure of different angles. Similarly, it is far from the simultaneous reduction of cooling/heating energy and lighting energy by harmonizing the shielding factor by heat blocking and the visible light transmittance.

On the other hand, Patent Publication No. 10-2017-0032256 (published on March 22, 2017) is a slat and Although the manufacturing method is proposed, since this slat is inherently opaque, it is irrelevant to the simultaneous reduction of cooling/heating energy and lighting energy by harmonizing the shielding factor by thermal insulation and the visible light transmittance.

Korean Registered Patent No. 1236332 (registered on February 18, 2013) Registered Patent No. 1758919 (registered on October 2, 2017) Publication No. 10-2017-0032256 (published on March 22, 2017)

Therefore, the first object of the present invention is to effectively block radiant heat through shielding of direct solar radiation by demonstrating the combined effect of shading, heat shading and lighting, thereby reducing cooling energy in summer and heating heat loss in winter, while reducing the uniformity and brightness of natural light. It is to provide blind slats capable of simultaneously saving cooling and heating energy and lighting energy by harmonizing the shielding coefficient by heat blocking and visible light transmittance, which can create a comfortable indoor environment.

A second object of the present invention is to provide a blind slat that effectively blocks infrared rays and ultraviolet rays while passing a significant portion of visible rays, thereby exhibiting good lighting properties.

A third object of the present invention is to provide a blind slat that is free from thermal deformation due to solar radiation, is lightweight and has high structural rigidity, and has an excellent heat blocking effect by an air layer.

A fourth object of the present invention is to provide blinds to which blind slats are applied according to the above-mentioned objects.

The first to third objects of the present invention described above are a transparent outer plate and an inner plate extending parallel to each other in the longitudinal direction at a distance of 1 to 20 mm to form a heat insulating air layer; This can be smoothly achieved by blind slats including a thermal barrier layer formed on the outer surfaces of the inner and outer plates.

In addition, the connecting rod formed along the longitudinal direction of the upper and lower ends of the outer plate and the inner plate; a plurality of supports located inside between the upper and lower ends of the outer plate and the inner plate along the longitudinal direction; The inner plate and the outer plate, the heat insulating layer, and the connecting rod may be integrally formed with the support.

In addition, at both ends of the outer plate and the inner plate in the longitudinal direction, finishing materials fitted to upper and lower ends of the support, the outer plate, and the inner plate may be included.

Here, the outer and inner plates are polycarbonate (PC), polymethyl methacrylate (PMMA), styrene-acrylonitrile (SAN) resin, acrylonitrile-butadiene-styrene (ABS) resin, polypropylene (PP) , a thermoplastic resin made of polyvinyl chloride (PVC), or polystyrene (PS); The above thermal barrier layer is a thermal barrier metal oxide made of antimony doped tin oxide (ATO), blue tungsten trioxide (Blue WO ₃ ), indium tin oxide (ITO), titanium nitride (TIN), or any mixture thereof. contained in an amount of 0.01 to 3% by weight in the thermoplastic resin; The outer and inner plates described above and the thermal barrier layer described above are integrally formed by special hollow double extrusion molding.

Also, optionally, an antibacterial layer or Ag, TiO ₂ , nano Cu, or an antibacterial layer obtained by coating and curing a thermosetting resin containing an antibacterial filler made of Ag, TiO ₂ , nano Cu, or any mixture thereof on the above thermal barrier layer, or It may further include an antibacterial layer attached to a film containing an antibacterial filler made of any mixture thereof.

The fourth object of the present invention described above can be smoothly achieved by a blind including a plurality of the aforementioned blind slats.

The blind may be in the form of a shutter-type roll blind in which vertically adjacent blind slats are connected by a dumbbell-shaped connector inserted into the recess and move up and down along guide rails located at both ends.

In addition, the blind may be in the form of a Venetian blind including a tadpole-shaped heat blocking member in which upper and lower blind slats are inserted into the concave zone.

Blind slats and blinds including them according to the present invention effectively block radiant heat through shielding of direct solar radiation by exhibiting complex effects of shading, heat shading, and lighting, thereby reducing cooling energy in summer and heating heat loss in winter, while balancing natural light and In order to create a comfortable indoor environment by reducing glare, it is possible to simultaneously reduce cooling and heating energy and lighting energy by harmonizing the shielding factor by heat blocking and the visible light transmittance, as well as effectively blocking infrared and ultraviolet rays while preventing visible rays. Since it shows good lighting properties by passing a significant portion of silver, it is possible to save lighting energy, has no thermal deformation due to solar radiation, is lightweight and has high structural rigidity, and has excellent heat blocking effect by the air layer.

1 is a perspective view of a blind slat according to the present invention.
Figure 2 is an enlarged assembly explanatory view of Figure 1;
3 is a side view of a blind slat including a partially enlarged model cross-sectional structure according to the present invention.
4 is a side view of another blind slat including a partially enlarged schematic cross-sectional structure according to the present invention.
5 is a side picture of a blind slat according to the present invention.
6 is a view showing a slat coupling structure in the form of a roll blind of a shutter type.
FIG. 7 is a view showing a state in which the rails of FIG. 6 are mounted.
8 is a schematic diagram showing a blind in the form of a Venetian blind including a heat blocking member.
9 is a closed state diagram of the blind according to the present invention.
10 is an open state diagram of a blind according to the present invention.

First, the term “blinds” used throughout this specification refers to Roman blinds, Austrian blinds, Venetian blinds, roller blinds, vertical blinds, etc. It is defined with a meaning including.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a perspective view of a blind slat 1 according to the present invention, 2 is an enlarged assembly explanatory view of FIG. 1, FIG. 3 is a side view of a blind slat 1 including a partially enlarged model cross-sectional structure according to the present invention, and FIG. 4 includes a partially enlarged model cross-sectional structure according to the present invention. It is a side view of another blind slat 1, and FIG. 5 is a side picture of the actual product of the blind slat 1 according to the present invention, which will be referred to together for convenience of description.

The basic structure of the blind slats 1 according to the present invention is a transparent inner plate 2 and an outer plate 3 extending parallel to each other in the longitudinal direction at a distance of 1 to 20 mm to form an insulating air layer 4, and the inner plate ( 2) and the 'C'-shaped connecting rod 5 connecting the upper and lower ends of the outer plate 3 along the longitudinal direction, and the inner plate 2 and the outer plate 3 on the inside between the upper and lower ends of the above-described length It includes a plurality of supports 6 positioned along the direction.

In general, blind slats have a length of about 2500 mm and are installed horizontally by connecting a plurality of them in the air, so bending due to gravity is easy to occur. (6), so it has high structural rigidity.

The number of the above-mentioned supports 6 is appropriate if it is about 1 or 2, but in some cases, it can also be 3 or more.

On the other hand, optionally, in the blind slats 1 according to the present invention, the support 6 and the upper and lower ends of the inner plate 2 and the outer plate 3 are provided at both ends in the longitudinal direction of the inner plate 2 and the outer plate 2. The finishing material 9 may be inserted in the.

The above finishing material 9 is the opposite side of the connecting rod 5 connecting the fitting part 9a which is fitted and fixed to the support 6 on one side of the body 9c and the inner plate 2 and the outer plate 3. It includes a press-fitting part 9b fitted inside, and by fixing the above-described finishing material 9 to both sides of the blind slats 1, the thermal conductivity of air at 1 atmospheric pressure of 293K is 0.0267W/mK, and the thermal conductivity of sealed air It can be further reduced to 0.023 W/mK.

As shown in FIG. 3, the blind slats 1 according to the present invention include an inner plate 2 and an outer plate 3 disposed spaced apart from each other above and below the air layer 4, and the inner plate 2 and the outer plate 3 described above. ), and the inner plate (2) and the outer plate (3), the heat insulating layer (7), the connector (5), and the support (6) are integrally formed by special hollow double extrusion molding. is formed with

The inner plate 2 and the outer plate 3 described above are not particularly limited in the present invention, but polycarbonate (PC), polymethyl methacrylate (PMMA), styrene-acrylonitrile (SAN) resin, acrylonitrile -Can be formed of a transparent thermoplastic resin made of butadiene-styrene (ABS) resin, polypropylene (PP), polyvinyl chloride (PVC), or polystyrene (PS).

In addition, the above thermal barrier layer 7 is ATO (Antimony doped tin oxide), Blue WO ₃ (Blue Tungsten trioxide), ITO (Indium Tin Oxide), TIN (Titanium nitride) having good ultraviolet and infrared blocking properties among the above thermoplastic resins. ), cesium tungsten oxide (CTO (Cesium Tungsten oxide), or a layer containing a thermal barrier metal oxide made of any mixture thereof in an amount of 0.01 to 3% by weight, whereby the light transmittance is in the range of 1 to 90% can be properly controlled.

In the present invention, the heat barrier metal oxide is a mixture of ATO (10 to 50% by weight), TIN (5 to 40% by weight), ITO (3 to 10% by weight) Blue WO ₃ (5 to 45% by weight) .

Specifically, ATO has a spherical average particle size of 5-15 nm, Blue WO ₃ has a linear average particle length of 50-60 nm, TIN has a polygonal average particle size of 20-50 nm, and ITO has a linear average particle size of 20-50 nm. An average particle length of 20-30 nm is used.

The finer the heat-blocking metal oxide, the better the heat-blocking and light-transmitting properties, but much effort and time are required for atomization. There is a problem with

Therefore, in the present invention, it is preferable to use a mixture of the above-described heat-blocking metal oxides having different types and average particle diameters, and the content thereof may be variously changed depending on factors such as the type of object to be applied, thermal insulation, and transparency. However, generally speaking, if it is less than the above range, there is a fear that the heat blocking effect may be reduced, and conversely, if it exceeds the above range, there is a fear that economical efficiency and light transmittance may be reduced.

In addition, in the present invention, organic metal complexes such as diatearyldimonium chloride, phthalocyanine-based compounds, and boron-based compounds may be used in combination as a thermal barrier compound in addition to the above metal oxides. After being atomized, it can be dispersed in an organic solvent such as ethanol for use, so it can be adopted in terms of convenience of use and control of the mixing amount.

On the other hand, the blind slats 1 according to the present invention optionally contain sugars such as phenyl benzidazole sulfonic acid, titanium oxide, butyl methoxydibenzoylmethane, Cinoxate, and/or benzophenone, as needed. An industry-known sunscreen may be included in an amount of 0.001 to 1% by weight, and in this case, the mixing amount of the metal oxide may be reduced by the mixing amount.

If the content of the sunscreen is less than 0.001% by weight, there is a risk that sufficient sunscreen effect may not be obtained, and conversely, even if it exceeds 1% by weight, it is difficult to expect a satisfactory degree of synergistic effect of sunscreen.

In addition, in the present invention, optionally, an antibacterial layer coated with a thermosetting resin containing an antibacterial filler made of Ag, TiO ₂ , nano Cu, or any mixture thereof is placed on the above thermal barrier layer and cured, or Ag, An antibacterial layer made of an antibacterial filler-treated adhesive film made of TiO ₂ , nano Cu, or any mixture thereof may be formed.

Also, if necessary, a protective layer 8 may be formed as a hard coating layer on the heat barrier layer 7 or the antibacterial layer to enhance scratch resistance.

Next, the blind 10 according to the present invention to which the blind slats 1 according to the present invention is applied will be described.

6 is a view illustrating a coupling structure of blind slats 1 according to the present invention, and FIG. 7 is a view showing a state in which the blind 10 according to the present invention of FIG. 6 is mounted on the guide rail 20.

The illustrated example shows a shutter-type roll blind type, and dumbbell-shaped connectors 11 are inserted into the connecting rods 5 of the blind slats 1 adjacent to each other according to the present invention and connected to each other, convection and radiant heat In order to improve the blocking function, guide rails 20 with intaglio grooves located at both ends of the blind 10 are installed to install a structure in which both ends of the blind slats 1 slide up and down and can be wound on the top. indicates that there is

8 is a schematic diagram showing a blind 10 according to the present invention in the form of a Venetian blind including a heat blocking member 12, in the illustrated example, vertically adjacent blind slats 1 are inserted into a connecting rod 5 Ji includes a tadpole-shaped heat blocking member 12, and when the blind 10 is closed by pulling the operating line, the space between the blind slats 1 is completely closed by the heat blocking member, increasing the heat blocking effect. .

It is preferable that the tadpole-shaped thermal barrier member 12 is made of an elastic material such as silicone or polyethylene, which has good adhesion and good weather resistance.

Meanwhile, in the blind 10 according to the present invention, some or all of the slats constituting the blind may be used as the slats 1 for the blind according to the present invention, specifically, the slats constituting the upper and/or central portion of the blind. Of course, the slats 1 for blinds according to the present invention are used, and conventional translucent or opaque slats may be used as the slats constituting the lower part, or vice versa.

Example:

Using polymethyl methacrylate (PMMA) as a thermoplastic resin and varying the type of heat-blocking compound as shown in Table 1 below, blind slats having different cross-sections were manufactured, and then physical properties including light transmittance were measured, The results are shown in Table 1 below.

Test Items Example 1 Example 2 Example 3 Example 4 Example
5 train cutoff
compound ATO /CTO /MTO (composite) (% by weight) ATO
0.12 CTO
0.12 CTO
0.12 CTO
0.12 MTO
0.12 Extrusion type Section type -
single / hollow straight half moon S type straight hollow sun block VLT (permeability) 78.4 77.00 73.00 67.5 59.7 UVR (ultraviolet rays protection rate) 99.5 99.8 99.5 99.5 100 IRR (Infrared Rejection Rate) 80.4 74.8 77.4 82.0 97.20 ROCKWELL Hardness 125.9 125.8 125.5 125.7 137.8 importance 1.197 1.194 1.197 1.197 1.119 The tensile strength 30mm/min 586 617 563 612 733 elongation 132 117 120 120 130 flexural strength 30mm/min 940 945 936 973 1020 flexural elasticity 21801 22947 22212 22986 32200 impact strength 1/8“ 81 85 85 80 86 1/4“ 9 8 8 7.8 10.2 HDT (18.6kg/cm2) 113 137 135.2 133.2 149.8 MI (300℃/1.2kg) 9.8 9,7 9.8 7.2 8.3 flame retardant V0 V0 V0 V0 V0

From the above results, it was confirmed that the blind slat, in which the cross section was made in a hollow shape to form an air layer, had excellent heat blocking effect by blocking ultraviolet and infrared rays, met the conditions for transmittance of visible light, and also had satisfactory structural rigidity.

1: blind slats according to the present invention
2: inner plate 3: outer plate
4: air layer 5: connecting rod
6: support 7: heat barrier layer
8: protective layer 9: finishing material
9a: fitting part 9b: press-fitting part
9c: body
10: blind according to the present invention
11: connector 12: thermal barrier member
20: guide rail

Claims (8)

Transparent outer and inner plates extending parallel to each other in the longitudinal direction at a distance of 1 to 20 mm to form an insulating air layer;
A blind slat comprising a thermal barrier layer formed on the outer surfaces of the inner and outer plates. According to claim 1, Connecting rods formed along the longitudinal direction of the upper and lower ends of the outer plate and the inner plate; a plurality of supports located inside between the upper and lower ends of the outer plate and the inner plate along the longitudinal direction; A blind slat in which the above inner and outer plates, the heat insulating layer, and the connecting rod are integrally formed with the support. The blind slat according to claim 1, comprising finishing materials inserted into upper and lower ends of the support, the outer plate, and the inner plate at both ends of the outer plate and the inner plate in the longitudinal direction. According to claim 1,
The above outer and inner plates are polycarbonate (PC), polymethyl methacrylate (PMMA), styrene-acrylonitrile (SAN) resin, acrylonitrile-butadiene-styrene (ABS) resin, polypropylene (PP), poly Any one thermoplastic resin selected from the group consisting of vinyl chloride (PVC) and polystyrene (PS);
The thermal barrier layer is at least one thermal barrier metal oxide selected from the group consisting of antimony doped tin oxide (ATO), blue tungsten trioxide (Blue WO ₃ ), indium tin oxide (ITO), and titanium nitride (TIN). It is contained in an amount of 0.01 to 3% by weight in the above thermoplastic resin;
The above outer and inner plates and the above heat barrier layer are integrally formed by special hollow double extrusion molding.
blind slats. The method of claim 1, wherein the antibacterial layer or Ag, TiO ₂ and nano Cu is formed by coating a thermosetting resin containing an antibacterial filler selected from the group consisting of Ag, TiO ₂ and nano Cu on the heat barrier layer. Blind slats further comprising an antibacterial layer attached with a film containing an antibacterial filler selected from the group. A blind comprising a plurality of blind slats according to claim 1. [Claim 7] The blind according to claim 6, wherein vertically adjacent blind slats are connected by dumbbell-shaped connectors inserted into the connecting rod, and are in the form of shutter-type roll blinds that move up and down along guide rails located at both ends. [Claim 7] The blind according to claim 6, wherein upper and lower blind slats are in the form of Venetian blinds including tadpole-shaped heat blocking members inserted into the connecting rods.

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