Patent Application
20220349246
The invention relates to a switchable optical device comprising a first substrate, a first conductive layer, a switchable layer, a second conductive layer and a second substrate. Further, the invention relates to a switchable glazing unit comprising at least one glass pane and at least one switchable optical device.
The review article by R. Baetens et al. “Properties, requirements and possibilities of smart windows for dynamic daylight and solar energy control in buildings: A state-of-the-art review”, Solar Energy Materials & Solar Cells 94 (2010) pages 87-105 describes tintable smart windows. Smart windows can make use of several technologies for modulating the transmittance of light such as devices based on electrochromism, liquid crystal devices and electrophoretic or suspended-particle devices. Liquid crystal based devices employ a change in the orientation of liquid crystal molecules between two conductive electrodes by applying an electric field which results in a change of their transmittance.
Liquid crystal based devices usually comprise in this order a first substrate, a switchable layer and a second substrate. The switchable layer comprises at least one liquid crystalline material. The two substrates are coated with a transparent electrode to allow control of the switchable layer by means of an electric field.
In smart windows, the device for modulating the transmittance of light, in the following referred to as switchable optical device, is usually laminated to a further sheet or carrier glass sheet or between two further substrates or carrier glass substrates for protection of the switchable optical device and for mechanical rigidity. In this lamination process, a glass sheet is bonded to a substrate of the switchable optical device by means of a thermoplastic interlayer. In the lamination process, the interlayer is arranged between the carrier glass sheet(s) and the at least one switchable optical device. In a subsequent treatment, which usually involves application of heat and/or elevated pressure or reduced pressure, the at least one sheet, the interlayer and the switchable optical element are bonded.
A smart window may comprise additional panes which form an insulated glazing unit. Further, the smart windows may comprise additional components such as frame for mechanically mounting of the switchable optical device and/or of further panes.
The switchable optical devices are sensitive to dimensional distortions of the substrates. In most switchable devices, such as liquid crystal based devices, the optical properties are strongly dependent on the thickness of the switchable layer. In case of a mechanically distorted substrate, the thickness of the switchable layer is non-uniform resulting in visible changes of the optical properties. Such distortions may occur when laminating the switchable optical device to a sheet having corrugations. This problem is known in the field of display panels and is discussed in U.S. Pat. No. 8,920,592 B2. Smart windows are usually larger than typical LCD displays and may have areas in excess of several square meters. Thus, the problem of dimensional distortions of the devices also applies to smart windows.
Further, the substrates of the switchable optical device are subject to distortions due to mechanical stress. Such mechanical stress may be caused by combining materials having different coefficients of thermal expansion.
GB 2497358 A discloses a method of framing and installing a viewing panel in an aperture of a door. The viewing panel is installed by using a frame which comprises an essentially U-shaped bracket. A portion of the viewing panel is received between two opposing securing members of the bracket. The framed viewing panel is then installed in an aperture of a door. One of the securing members is positioned adjacent to the outer surface of the door so that lateral forces act only in one direction on the fixing means.
WO 02/29471 A1 discloses methods for retrofitting windows with switchable and non-switchable window enhancements. A window enhancement, such as a suspended particle device (SPD) film is mounted on a window using mounting means such as securing strips. The mounting means are placed on a viewing pane of the window. A gap having the same thickness as the mounting means is formed between the window enhancement and the viewing pane. Members may be positioned in the gap in order to maintain the width of the gap.
WO 2016/086062 A1 describes electrochromic windows which may be installed proximate pre-existing windows and corresponding methods and tools. Further, insulated glazing units (IGU) are disclosed wherein one lite includes an electrochromic device. Such an IGU may comprise a vent module to force air through a gap between the electrochromic window and the existing window pane. Further, retainers are disclosed to support a new window which is sealed or glued to a pre-existing window in case the seal or adhesive fails.
The known methods for mounting glass elements or switchable window elements provide securing members or securing strips which contact the element to be mounted at the respective edges. Further elements are required to provide for the necessary electrical connections.
It is an object of the present invention to provide a switchable optical device which may be easily integrated in a smart window. It is a further object of the invention to provide a switchable glazing unit having uniform optical properties.
A switchable optical device comprising in this order a first substrate, a first conductive layer, a switchable layer, a second conductive layer and a second substrate is provided. The switchable optical device further comprises one or both of the following aspects:
In a first aspect i) the first conductive layer comprises a first contact zone and a second contact zone, wherein the first contact zone is electrically insulated from the second contact zone and wherein the switchable optical device comprises an electrical interconnect for electrically connecting the second contact zone of the first conductive layer to the second conductive layer.
In a second aspect ii) the switchable optical device comprises at least one further sheet which is laminated to the first substrate and/or the second substrate, wherein first substrate, the second substrate and the at least one further sheet, have essentially the same thermal expansion coefficient.
The first substrate, the second conductive layer, the switchable layer, the second conductive layer and a second substrate form a switchable element. The switchable optical device may comprise a single switchable element or may comprise more than one switchable element. For example, the switchable element may comprise two or three switchable elements.
The switchable element has at least two switching states. The switching states may, for example, include a clear and transparent state, a dark state, a hazy state and mixtures of at least two of these states. Areas of the switchable element in which elements such as glue lines, electric connections and electric driving circuits are located are not affected by switching of the switching layer and are referred to as non-switchable areas.
Preferably, the transmission through the switchable optical device for at least one of the states, preferably in a transparent state, is at least 40% for light in the visible spectrum. More preferably the transmission is at least 50%. The visible spectrum is defined as light having a wavelength of from 380 nm to 780 nm.
Preferably, the switchable optical device comprises at least two switchable elements. Preferably, switchable elements of different types are combined. The switchable elements may be stacked on top of each other and joined, for example, by lamination or by means of an optically clear adhesive. The switchable optical device may, for example, include a first switchable element having a hazy state and a clear state, and a second switchable element having a dark state and a clear bright state.
The optical state of the switchable layer of the switchable element is controlled by means of the two conductive layers. For providing control signals to the two conductive layers, the switchable optical device may be connected to a controller. The first and second conductive layers have contact zones which are located outside of a switchable area of the switchable optical device. The area of the conductive layers located within the switchable area serves as electrode zone. The switchable area of the switchable optical device is the area, in which the optical properties may be controlled by switching the state of the switchable layer.
Preferably, the switchable element is a liquid crystal based element. In this case, the switching layer comprises a liquid crystalline medium. The state of the liquid crystalline medium is controlled by an electric field which is applied by means of the two electrodes. The liquid crystalline medium may comprise further components such as spacers in order to ensure a uniform thickness of the liquid crystal based switchable layer.
Preferably, the switchable element is a liquid crystal (LC) device selected from modes based on either LC-dye mixtures/LC without dyes and modes described by geometry of twisted nematic, super twisted nematic, planar or vertical ECB nematic, Heilmeier, vertically aligned, twisted vertical aligned, highly twisted nematic, polymer stabilized cholesteric texture (PSCT), polymer networked liquid crystal (PNLC) or polymer dispersed liquid crystal (PDLC). The device may include further functional layers such as, for example, color filters, alignment layers and/or polarizers. Optionally, two or more of such switchable elements may be stacked in the switchable optical device.
Preferably, the liquid crystal based element additionally comprises an alignment film located on the first substrate layer and/or the second substrate layer. The alignment film is preferably arranged on the side facing the switchable layer. If an electrode is also located on the respective substrate layer, the alignment film is preferably arranged on the conductive layer so that the alignment film is in direct contact with the switchable layer. The alignment film may be rubbed in an alignment direction.
The two substrate layers and the liquid-crystalline medium are arranged as a cell wherein the liquid-crystalline medium is placed in the gap formed by the two control layers. The size of the gap is preferably from 1 μm to 300 μm, preferably from 3 μm to 100 μm and more preferably from 5 μm to 100 μm, and most preferably from 10 μm to 50 μm. The cell is usually sealed by means of glue lines located at or near the edges.
The switchable layer of a liquid crystal based switchable element comprises a liquid-crystalline medium. A liquid-crystalline medium is defined as a substance having the properties of a liquid crystal. Typical liquid-crystalline media comprise at least one composition having elongated rod-shaped molecules. The liquid-crystalline media used in conjunction with the present invention have at least two states. The state of the liquid-crystalline medium is controlled using an electric field which is generated by an AC driving voltage applied between the two electrodes.
Preferably, the switchable element is a suspended particle device. In this case, the switchable layer preferably comprises particles suspended in a liquid. Usually, the particles have a rod-like shape. Without an applied electric field, the suspended particles are randomly organized. In this state, the particles block and absorb light. When an electric field is applied, the suspended particles align and light may pass through the switching layer.
Preferably, the switchable element is an electrochromic device. In electrochromic devices, a switchable layer is used which is able to change its optical properties reversibly if an electric field is applied. This change of optical properties is associated with ion insertion and extraction processes. The switchable layer is sandwiched between the two substrates coated with the conductive layers and usually comprises in this order one or more cathodic electroactive layer(s), an ion conductor and an ion-storage film or one or more complementary anodic electroactive layers.
The first and/or second substrate is preferably optically isotropic and transparent. The first and second substrates are preferably independently selected from a glass or a transparent polymer. Examples for a suitable glass include, for example, alkaline earth boro-aluminosilicate glass, chemically toughened glass, aluminosilicate glass, borosilicate glass and soda lime glass. Examples for suitable transparent polymers include polycarbonate (PC), cyclo-olefin polymer (COP), polyethylene terephthalate (PET), polyimide and polyethylene naphthalate (PEN).
Preferably, same material is used for both substrates.
The substrates may have any size and shape. For example, the substrates may have a square or rectangular shape. Preferably, the first and second substrates have the same size and shape. Alternatively, the second substrate may be of smaller size or may have a different shape. For example, the second substrate may comprise cut-outs or cut corners to allow access to the first conductive layer of the switchable optical device.
In order to apply an electric field to the switchable layer, the first and second conductive layers are provided. An electric field is generated between the two electrodes by applying a voltage to the electrodes, for example by means of a driving signal. Preferably, the electrodes are transparent conductive layers, wherein the switchable layer is arranged between two transparent conductive layers. A power supply apparatus which may include a driving signal generator and cables may be used to supply the voltage to the electrodes.
The first and/or second transparent conductive layers are, for example, based on a thin layer of indium tin oxide (ITO), fluorine tin oxide (FTO), aluminum zinc oxide (AZO), indium gallium zinc oxide (IGZO) or antimony tin oxide (ATO). Further, the conductive layers may be configured as polymer matrix comprising conductive nanorods such as silver nanorods. The electrodes are preferably applied to the two substrates and are arranged such that the transparent electrodes face each other. A SiOx coating may optionally be used underneath or as topcoat.
The switchable optical device of the second aspect ii) comprises at least one further sheet which is laminated to the first substrate and/or the second substrate. A further sheet may also be used in conjunction with the switchable optical device of the first aspect i).
The further sheet is preferably optically transparent and may be selected from a polymer or a glass.
Suitable materials for the further sheet include the same materials that may be used for the first and/or second substrate. Further, it is possible to use other materials such as, for example, float glass or downdraw glass. The glass may also have been subjected to a pre-processing step like tempering, toughening and/or coating or sputtering. The glass can be, for example, soda-lime glass, borosilicate glass, boro-aluminosilicate glass or aluminosilicate glass.
Preferably, the at least one further sheet is made from the same material as the two substrates.
Preferably, the thickness of the at least one further sheet is in the range of from 2 mm to 10 mm, wherein a range of from 2 to 6 mm is more preferred.
The thickness of the at least one further sheet is preferable of the same order of magnitude as the thickness of the switchable element formed by the two substrates and all the layers between the two substrates. Accordingly, the thickness of the switchable element is the sum of the thicknesses of the layers between, the first and second substrate and the thickness of the two substrates. The thickness of the at least one further sheet is preferably less than 110% of the thickness of the switchable element.
For lamination, a lamination sheet (interlayer) is arranged between the at least one further sheet and the first and/or second substrate of the switchable element. In a subsequent treatment, which usually involves application of heat and/or elevated pressure or reduced pressure, the at least one sheet, the interlayer and the switchable element are bonded.
Suitable lamination sheets include, for example, an ionoplast, ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or thermoplastic polyurethane (TPU).
A suitable ionoplast is available under the trade name SentryGlas.
Alternatively, the at least one further sheet and the at least one switchable element may be bonded by applying an adhesive at the interface between the further sheet and the first substrate layer. In particular, an optically clear adhesive (OCA) may be used.
Preferably, the used first substrate, second substrate and/or the at least one further sheet are essentially flat and microcorrugations are less than 0.3 μm per 20 mm measurement length (measured using cut-off wavelength 0.8 to 8 μm). The microcorrugations or flatness of the respective substrate or sheet may, for example, be measured by means of touch probes, or optical measurement methods based on interference or ellipsometry.
Examples for suitable flat glass substrates are, for example alkaline earth boro-aluminosilicate glass available from Corning under the trade name Corning® Eagle XG® Glass. Further suitable examples include Corning® Gorilla™ Glass and polished borofloat glass available from Asahi.
Aspect i) of the switchable optical device allows supplying the electrical control signal for the second conductive electrode by applying the electrical control signal to the second contact zone of the first conductive layer. Thus, both conductive layers may be contacted by the respective contact zones of the first conductive layers. The control signal for the second conductive layer is supplied by means of the electrical interconnect.
Preferably, the electrical interconnect is selected from conductive adhesives, structured conductive films, metal spacers and combinations thereof.
The electrical interconnect has a thickness sufficient to bridge the gap between the first conductive layer and the second conductive layer. The electrical interconnect is arranged in the second contact zone. In case a conductive adhesive is used, the adhesive is preferably provided in form of a glue line arranged in the second contact zone. Directly after the application, the thickness of the glue line is preferably larger than the thickness of the gap. After the layer structure of the switchable element has been assembled, the glue line is squashed and has a final thickness identical to the gap thickness. The electrically conductive adhesive may be an isotropic or anisotropic conductive adhesive.
In case metal spacers are used, the metal is preferably selected from gold, copper, nickel and alloys of the described metals. Further suitable spacer materials include graphite and other carbon modifications. The spacers preferably have a spherical shape having the same diameter as the size of the gap or are slightly larger than the size of the gap. The spacers may be combined with a conductive or a non-conductive adhesive.
In case a structured conductive film is used, the conductive film comprises vertically extending structures such as corrugations, wherein the height of the structures is sufficient to bridge the gap between the first and second conductive layers.
The first contact zone of the first substrate preferably extends along at least two edges of the first substrate. The first contact zone may have a “L”-shape, wherein one leg extends over a first part of a first edge of the substrate and over the entire length of an adjacent second edge of the first substrate. The first and second contact zones are separated by an insulated zone. The second contact zone preferably extends along the entire length of at least one edge of the first substrate. Preferably, the second contact zone extends over the entire length of a third edge of the first substrate which is adjacent to the first edge.
Preferably, the first and second contact zones are arranged such that the first contact zone and the second contact zone abut against the same edge of the first substrate. Preferably, the first contact zone and the second contact zone both abut against the first edge of the first substrate and are separated by the insulated zone.
Preferably, a metallic conductor extends over the entire area of the first contact zone and/or a metallic conductor extends over the entire area of the second contact zone. Preferably, the metallic conductor is configured as a multi-layer film structure comprising in this order gold, chrome and copper. The multi-layer film structure may be obtained in a sputter process. Alternatively, other film forming techniques such as galvanic deposition, physical vapor deposition (PVD) or chemical vapor deposition (CVP) may be used. Additionally or alternatively, a metal conductor such as a metal strip may be bonded to the first conductive layer in order to form the metallic conductor.
In order to allow for electrically contacting of the first conductive layer, it is preferred to configure and/or arrange the second substrate such that at least a part of the first contact zone and of the second contact zone are not covered by the second substrate.
Preferably, the second substrate is smaller than the first substrate and is arranged centered above the first substrate or is aligned to the first edge of the first substrate in one dimension and centered in the other dimension. Alternatively, the second substrate comprises at least one cut corner and/or multiple cut-outs arranged on at least one edge of the second substrate.
In case of cut corners, it is preferred to arrange to cut corners such that they are arranged along a first edge of the second substrate and to arrange the second substrate such that the first edge of the second substrate is aligned to the first edge of the first substrate.
The multiple cut-outs are preferably configured as a sinusoidal shaped edge or multiple cut-outs shaped as half circles, rectangles or rounded rectangles, respectively. The multiple cut-outs are arranged such that when the second substrate is placed above the first substrate, at least one cut-out is over the first contact zone and at least one cut-out is over the second contact zone.
Preferably, the corner cut and/or the multiple cut-outs are produced by laser cutting. Laser cutting produces smooth edges which differ from other cutting methods. The risk of breakage is reduced by the surface finish obtained by laser cutting
Preferably, the switchable optical device further comprises a first metal contact sheet which contacts the first contact zone and a second metal contact sheet which contacts the second contact zone, wherein the first and second metal contact sheets extend beyond the first substrate and are bent such that they cover parts of an edge-surface of the first substrate and, if present, of an edge-surface of the further sheet laminated to the first substrate.
Preferably, the first and/or second metal contact sheets partially cover an edge surface of the first edge of the first substrate.
Preferably, a first cable is connected to the first contact zone and a second cable is connected to the second contact zone and/or the first electrical contact zone and the second electrical contact zone have metallized surfaces configured for a spring contact.
Cables may, for example, be connected to the respective contact zone of the first conductive layer be means of welding or soldering, in particular by means of ultrasonic soldering. The cables may be connected directly to the first conductive layer or may be connected to a metallic conductor of the respective contact zone. Preferably, the cables connections are arranged on the same edge of the first substrate, in particular the first edge of the first substrate.
The cable connections in the respective contact zone are preferably protected by means of a cover. For example, the connections are covered by means of a potting material.
The metallized surface may, for example, be a multi-layer film structure. The metallized surface may be a part of a metallic conductor arranged in the first and/or second contact zone.
In the second aspect ii) the switchable optical device comprises at least one further sheet which is laminated to the first substrate and/or the second substrate. The first substrate, the second substrate and the at least one further sheet, have essentially the same thermal expansion coefficient.
The term “essentially the same coefficient of thermal expansion” means that only minor differences in the coefficient of thermal expansion exist between all substrates and glass sheets used in the switchable optical device. Preferably, the difference between the largest and the smallest coefficient of thermal expansion is less than 5% and more preferably less than 1%. Most preferably identical materials are used for the first substrate, the second substrate and the at least one further sheet so that all further sheets and substrates of the switchable optical device have the same coefficient of thermal expansion.
The switchable optical device of aspects i) and/or ii) may comprise additional features such as additional functional films and coatings.
Preferably, at least one of the first substrate, the second substrate and/or the at least one further sheet comprises a transparent electrical heater film. The heater film may be a transparent electrically conductive film. In particular, the heater film may be an ITO or FTO film.
For contacting of the heater film, electrical contacts similar to those described with respect of the first conductive layer may be used.
Further, a method for producing a switchable optical device is proposed.
In a first step a) a first substrate which is coated with the first conductive layer is provided. The first conductive layer may, for example, be a transparent ITO layer. The first conductive layer is structured, for example by means of a laser process, to form the insulated zone. The first substrate may be laminated to a further sheet by means of an interlayer.
In a second step b), first alignment layer for liquid crystals is applied. The first alignment layer is, for example, a polyimide layer. The first alignment layer is structured, for example by rubbing.
In a third step c), a glue line for forming a seal for liquid crystalline medium is applied. Also, an electrical interconnect is prepared by applying an adhesive comprising metal spacers. Optionally, the first alignment layer is partially removed before applying the glue line and/or before preparing the electrical interconnect.
In a forth step d), the liquid crystalline medium is provided, for example by means of one drop filling or inkjet printing. The liquid crystalline medium may comprise spacers to ensure a uniform thickness of the switchable layer.
A fifth step e) is performed in vacuum. Air is evacuated, for example in a vacuum assembly-unit and a second substrate is provided. The second substrate is placed onto the prepared glue line by means so that the second substrate is aligned to the first substrate. The second substrate is coated with a second conductive layer and also preferably comprises a second alignment layer.
In a last step f) the adhesives used in the glue line and the electrical interconnect are cured, for example by means of UV-radiation, by means of heat or by a combination of heat and UV-radiation.
Alternatively to steps d), e) and f) other methods for filling the cell with the liquid crystalline medium may be used. For example, the cell may be formed first by placing the second substrate onto the glue line and the cell may then be filled by means of a vacuum filling process.
In a further aspect of the invention, a switchable glazing unit comprising at least one glass pane and at least one switchable optical device is provided. The at least one switchable optical device is mechanically decoupled from the at least one glass pane of the glazing unit. Further, the switchable glazing unit comprises at least one of the following aspects:
In a first aspect a) the switchable glazing unit comprises means for electrically contacting the at least one switchable optical device which include at least one electrical spring contact.
In a second aspect b) the switchable glazing unit is constructed as an insulated glazing unit comprising two or more panes with gaps between the panes and the at least one switchable optical device is used as one of the panes of the insulated glazing unit.
In a third aspect c) the switchable glazing unit has at least one switchable optical device as described herein.
For mechanically decoupling of the switchable optical device from the at least one glass pane of the glazing unit, a bonding over the entire area of the switchable optical element is avoided. Instead, it is preferred to hold or attach the switchable optical element at or near the edges. Also, the switchable glazing unit is preferably constructed and arranged such that the at least one switchable optical device may freely expand or contract when temperature changes.
For holding the switchable optical device at its respective edges, the switchable glazing unit may comprise one or more holding elements and/or mounting elements. The holding element may, for example, have essentially a “U”-shaped profile for engaging the switchable optical element. The mounting element may, for example, be a spacer which is arranged between the switchable optical element or a window element and a pane of an existing window. The mounting element may be attached to the pane of an existing window, for example, by means of an adhesive.
The mounting element may alternatively be constructed as a rail which is attached to a pane of an existing window, such as an insulated glazing unit (IGU). A switchable optical element may then be installed by inserting the element into the rail.
Due to the mechanically decoupling, a dimensional change of a glass pane of the window is not directly transferred to the switchable optical device. This is especially important if the coefficient of thermal expansion of the at least one glass pane of the switchable glazing differs from the coefficient of expansion of the substrates and, if present, of the at least one further sheet of the switchable optical device.
For example, the coefficient of thermal expansion for soda-lime glass is α=9.2·10−6 1/K and the coefficient of thermal expansion for boro-silicate glass is α=3.2·10−6 1/K. Soda-lime glass is commonly used for window panes and boro-silicate glass is a typical glass used as substrate for liquid crystal based switchable optical devices. The thermal expansion may be approximated using the equation
ΔL˜αL0Δt
wherein ΔL is the change in length, L0 is the initial length and Δt is the change in temperature. For a temperature difference of e.g. 120° C. (for example the difference in temperature between 20° C. room temperature and a typical lamination temperature of 140° C. and room temperature), a soda-lime glass of a 3.5 meter length glass expands by ˜3.9 mm and the boro-silicate glass by ˜1.3 mm. If a switchable optical device comprising boro-silicate glass substrates would be bonded to a further sheet of soda-lime glass by lamination over the full surface area, such a difference in thermal expansion causes mechanical stress.
Preferably, the switchable glazing unit further comprises at least one window element comprising the at least one switchable optical device, a frame for mechanical decoupling and electrical contacting of the at least one switchable optical device and at least one electrical spring contact for contacting the at least one switchable optical device.
The frame preferably comprises at least one air channel. The air channel allows for ventilation of an air gap between the switchable optical device and the at least one glass pane of the switchable glazing unit.
Preferably, the frame is made from three types of frame profile parts, wherein the sides of the frame are formed respectively by a first profile part having a U-shaped profile and the top and bottom sides of the frame are formed respectively by a second profile part having a L-shaped profile and a third profile part having a rectangular profile. The second and third profile parts are combined to form a “U”-shape for receiving the switchable optical device.
Preferably, the material of the profile parts is selected from an electrically non-conducting material. Suitable examples of electrically non-conducting materials include wood, plastic materials and fiber reinforced plastic materials. The use of fiber reinforced plastic material is preferred; in particular glass fiber reinforced plastic materials. A suitable example for the plastic material is polyamide which, for example, is reinforced with 50% glass fibers.
Preferably, the switchable glazing unit further comprises electrical spring contacts for electrically contacting the at least one switchable window element. Additionally or alternatively, the switchable window element, preferably further comprises an electrical cable, an electrical socket or an electrical contact surface for electrically contacting of the switchable window element.
Preferably, the electrical spring contact for contacting the at least one switchable optical device according to aspect a) and/or for contacting the at least one switchable window element is configured as a bending spring or a spring loaded contact pin. Further, in order to improve corrosion resistance it is preferred to use plated noble metal contacts for the bending spring or the spring loaded contact pin. Preferably, gold is used as noble metal.
Preferably, the switchable glazing unit further comprises an insulated glazing unit having two or more panes with gaps between the panes and the at least one switchable optical device is arranged adjacent to one of the panes.
The insulated glazing unit comprises spacer elements between the panes.
In case the switchable optical device is arranged adjacent to one of the panes of an insulated glazing unit, the switchable glazing unit preferably comprises means for venting of a space between switchable optical device and the insulated glazing unit.
In case the switchable optical device is used as one of the panes of an insulated glazing unit according to aspect b) of the invention, the at least one switchable optical device may be used as a first pane, which, when the window is installed faces outwards, as a second pane, which when the window is installed faces inwards, or as a middle pane in case the insulated glazing unit comprises more than two panes.
Such an embodiment has the advantage that the total thickness of the switchable glazing unit can be reduced. For example, a thickness of the switchable glazing unit may be reduced to about 23 mm for use in vehicles, e.g. for train applications, marine or aviation or to less than 40 mm for architectural applications. The concept of introducing thin light-weighed switchable optical devices into the middle of a triple glazing insulated glazing unit means a weight reduction of about 40% while achieving at the same time better thermal stability and better g- and u-values.
In cases where the switchable optical device is used as or respectively in a second pane facing inwards or especially a middle pane and where the switchable optical device may have a tendency to absorb significant amounts of light and in particular heat, it can be preferable to provide a means to compensate for or respectively to dissipate unwanted or excessive heat input. Such means may include for example the use of heat-conducting films, heat-conducting gases, or in particular using different gases for different gap spaces, Peltier elements which optionally may be coupled with solar cells or thermoelements, solar fans, heat-controlling coatings etc.
In cases where the switchable optical device is used as or respectively in a first pane facing outwards, it is preferred that the switchable optical device is laminated to a strengthened or toughened glass, preferably thermally or chemically toughened glass, aluminosilicate glass or borosilicate glass and in particular aluminosilicate glass or borosilicate glass.
Preferably, at least one glass pane and/or at least one switchable optical device of the switchable glazing unit comprises a low-e coating. Preferably, the low-e coating is arranged on a surface of a switchable optical device or a glass pane which faces towards a gap of the insulated glazing unit.
In an embodiment it is also possible to provide, in addition or alternatively to a low-e coating, an anti-reflective coating on at least one surface of a glazing, a switchable optical device or a glass pane. In this case preferably a multilayer optical thin film coating of metal oxides is applied to give interference optical coated glass. The metal oxides can provide non-corroding, hard and durable coatings which are thus suited even for top layers or exterior surfaces. The anti-reflective coating may be applied to one or both sides of a glass pane and/or to one or more glass panes of an insulated glazing unit. It is particularly preferred that the anti-reflective coating is provided on the outside or exterior surface of the outermost pane, in particular the side facing the light source, of the glazing unit.
In the case that a switchable area of the at least one switchable optical device is smaller than an optically clear area of the at least one glass pane of the switchable glazing unit it is preferred that the switchable glazing unit additionally comprises a passepartout-frame for covering spacer-blocks and/or non-switching areas of the at least one switchable optical device.
Advantageously, the border of the passepartout-frame also obscures parts of the switchable optical device which are sensitive to degradation by light and or areas that are aesthetically not attractive. Such areas include parts of the switchable optical element that are not switching such as sealants, glue lines and/or electrical connectors. Usually, non-switching areas of the switchable optical element such as the sealing (glue lines), electric connections and/or electric driving circuits are located at or near the edges of the switchable optical device.
Preferably, the switchable glazing unit additionally comprising a UV-absorbing layer arranged prior to the at least one switchable optical device when viewed from the outward facing side of the switchable glazing unit.
The UV-absorbing layer may be a doped interlayer, in particular a doped PVB interlayer, a UV-paint, an adhesive film containing UV-protection or a printed or coated film of UV-absorbing material.
The at least one switchable optical device of the switchable glazing unit is preferably selected from liquid crystal based devices, electrochromic devices, gasochromic devices, thermochromic devices, thermally switchable devices, electrophoretic devices, suspended particle devices or combinations of at least two of these switchable optical devices.
Preferably, at least one glass pane and/or at least one switchable optical device of the switchable glazing unit comprises a transparent electrical heater film.
Preferably, the switchable glazing further comprises a controller for electrically controlling switching of the at least one switchable optical device. The controller is adapted for supplying electricals signals necessary for switching the at least one switchable optical device from one state to another state and/or for holding the at least one switchable optical device in a certain state. The electrical signal may be selected from direct-current signals and alternating current signals such as square wave, sine wave or arbitrary wave-form signals.
The switchable glazing unit may comprise additional elements such as a window frame.
The switchable glazing unit may be provided as a new device for first installation or replacement of existing windows of a building or a vehicle. Alternatively, the switchable glazing unit may be based on an existing window of a building or a vehicle which is retrofitted by combining the existing window with at least one switchable optical device.
It is a further aspect of the invention to provide a process for producing such a switchable glazing unit. The process comprising the steps of
a) providing a window comprising a window frame and at least one glass pane,
b) optionally attaching mounting elements to the at least one glass pane, and
c) attaching a switchable optical device by means of holding elements or a frame to the glass pane.
Alternatively, the process comprises the steps of
a) providing a window comprising a window frame and an insulated glazing unit,
b) disassembling the insulated glazing unit,
c) reassembling the insulated glazing unit, wherein a switchable optical device is used as one of the panes of the insulated glazing unit.
Preferably, the switchable optical device is one of the switchable optical devices described herein.
In a further aspect of the invention, a switchable window is provided which comprises a window frame and at least one of the described switchable optical devices and/or at least one of the described switchable glazing units.
Preferably, the switchable window is used as a window of a vehicle or building. The vehicle may, for example, be a land-based vehicle such as car, truck, bus or train, a ship, an airplane, or a spacecraft.
An insulated glazing unit (IGU) comprising a switchable optical device having two switchable elements is provided. The IGU comprises three panes, wherein the switchable optical device is used as middle pane. The first glass pane facing outside and the second glass pane facing towards the inside are made from a first type of glass and the substrates of the switchable optical devices are made from a second type of glass. The layer structure is given in table 1.
An insulated glazing unit (IGU) comprising a switchable optical device having only one switchable element is provided. The switchable optical device comprises two further sheets for enhancing the mechanical strength of the device. The IGU comprises three panes, wherein the switchable optical device is used as middle pane. The first glass pane facing outside and the second glass pane facing towards the inside are made from a first type of glass and the substrates of the switchable optical device as well as the further sheets are made from a second type of glass. The layer structure is given in table 2.
The drawings show:
In the embodiment shown in
The first conductive layer 14 is divided into a first area and a second area by means of an insulated zone 34. The first area comprises a first contact zone 30 and an electrode zone 29. The second area comprises a second contact zone 32. The first contact zone 30 and the second contact zone 32 as well as the insulted zone 34 are located in the non-switchable area 82 and the electrode zone 29 is located in the switchable area 80.
For supplying the electric driving signal to the second conductive layer 22, the second contact zone 32 of the first conductive layer 14 is used. The driving signal is transferred from the second contact zone 32 to the second conductive layer 22 by means of an electrical interconnect 38. In the embodiment of
The switchable optical device 10 of
The second substrate 24, see
In a first step a) shown in
Further, in the example depicted in
In a second step b) shown in
In a third step c) shown in
In a forth step d) shown in
A fifth step e) shown in
In a last step f) shown in
Due to the cut corners 44 of the second substrate 24, access is provided to a first electrical contact 58 in the first contact zone 30 and to a second electrical contact 60 in the second contact zone 32. By applying a driving signal to the first and second electrical contacts 58, 60, the state of the switchable optical device 10 may be controlled. The first and second electrical contacts 58, 60 abut against the first edge 86 of the first substrate 12 of the switchable optical device 10.
As already described with respect to
As shown in
In the second embodiment of
The first and second contact zones 30, 32 each comprise metal conductors 42 in the form of a sputtered metal film. In the embodiment shown in
In order to improve the electrical conductivity, a metal conductor 48 may be provided in the first contact zone 30 and the second contact zone 32, for example by means of sputtering of a metal film or by applying a conductive metal foil.
In order to improve the electrical conductivity, a metal conductor 48 may be provided in the first contact zone 30 and the second contact zone 32, for example by means of sputtering of a metal film or by applying a conductive metal foil.
The features of the different embodiments of the switchable optical device 10 may be combined. For example, the arrangement of the first contact zone 30 and of the second contact zone 32 as shown in the fifth and sixth embodiments of
In
The cut-outs 46 may be produced by means of laser cutting of the second substrate 24.
The switchable optical device 10 of
The film heaters 62, 64 are preferably constructed as transparent conductive film, for example an ITO or FTO film. When an electric current is applied to the film heater 62, 64, the film heater 62, 64 warms up due to the electrical resistance of the transparent conductive film.
In
The window element 100 comprises a switchable optical device 10 and a frame 101. The frame 101 comprises profile parts 102, 104, 106 (see
The frame 101 additionally comprises electrical spring contacts 110 for electrically contacting metallized surfaces 48 of the switchable optical device 10. In the section shown in
The frame 101 comprises the electrical spring contact 110 for contacting the metallized surface 48. The electrical spring contact 110 comprises a shaft 118 and a conductive rubber surface 112 which is in contact with the metallized surface 48 of the switchable optical device 10. A spring 116, which abuts a shoulder of the profile part 102 tensions the rubber surface 112 of the electrical spring contact 110 against the metallized surface 44 of the switchable optical device 10 to ensure a reliable electrical connection while at the same time avoiding mechanical stress. The cable 122 is secured to the shaft 118 by means of nuts 114.
A cable 122 is connected to the electrical spring contact 110 in order to supply a driving signal to the switchable optical device 10. The electrical spring contact 110 is protected by means of a cover 124.
A second profile part 104 and a third profile part 106 are joined and form a profile having essentially a “U”-shape. For assembling of the frame 101 around a switchable optical device 10, the two first profile parts 102 are provided and cut to the size of the switchable optical device. Further, two second profile parts 104 and two third profile parts 106 are provided and cut to the size of the switchable optical device 10. The two first profile parts 102 are arranged on opposing sides of the switchable optical device 10 such that the switchable optical device 10 engages in the recess of the U-shape. Then second profile parts 104 are respectively connected to third profile parts 106 by means of screws 108. As last step, the second parts 104 are connected to the first profile parts 102.
Preferably, the size of the frame 101 is chosen such that the switchable optical device 10 has space to expand in order to avoid mechanical stress due to thermal expansion.
The frame 101 may further comprise air channels 120 which allow the passage of air when the frame 101 is mounted in a window.
The switchable glazing unit 200 of
The first pane 202 and the second pane 206 are configured as glass panes. An example for the material of the glass panes is soda-lime glass, including tempered or heat-strengthened versions thereof, which may be produced in a float glass process.
The spacers 208 are attached to the panes 202, 204, 206 by means of a first seal 210 which is, for example, a butyl seal. The outward facing sides of the spacers 208 are sealed by means of a second seal 212 which is, for example, a polysulfone seal. The spacers 208 may comprise a desiccant.
The middle pane 204 is configured as a switchable optical device 10 which is received by a first holder 216 at the bottom and by a second holder 217 at the top. Both the first holder 216 and the second holder 217 have a recess for receiving the switchable optical device 10. Further holders may be arranged at the sides of the switchable optical device 10. At the second holder 217, a space 218 is arranged in order to accommodate for thermal expansion of the switchable optical device 10.
The switchable optical device 10 comprises the first substrate 12, the second substrate 24 and the functional layers forming the switchable element as described with respect to
In the embodiment shown in
The first holder 216 arranged at the bottom of the switchable optical device 10 comprises a spring contact 220 which in the embodiment of
For installation of the switchable glazing unit 200 in a window frame 310 (see
The switchable glazing unit 200 of
The first pane 202 and the second pane 206 are configured as glass panes. An example for the material of the glass panes is soda-lime glass which may be produced in a float glass process. The first pane 202 is, when the switchable glazing unit 200 is used as a window, arranged to face outwards as indicted in
The spacers 208 are attached to the panes 202, 204, 206 by means of a first seal 210 which is, for example, a butyl seal. The outward facing sides of the spacers 208 are sealed by means of a second seal 212 which is, for example, a polysulfone seal.
A switchable optical device 10 is used as middle pane 204. The switchable optical device 10 of the embodiment of
When installed in a window, it is preferred to use a support block having a channel for accommodating the cables 222.
The switchable optical device 10 comprises a further sheet 28 laminated to the first substrate 12. A metal contact sheet 68 is attached to the first conductive layer 14, see
The metal contact sheet 68 provides a contact surface which may be contacted by means of a spring contact 220. For example, a bending spring 228 may be used in a window frame 310 to contact the metal contact sheet 68, see
The switchable glazing unit 200 of
The second pane 206 is configured as a glass pane. An example for the material of the glass pane is soda-lime glass which may be produced in a float glass process. A switchable optical device 10 having a further sheet 28 as described with respect to
The spacers 208 are attached to the panes 202, 206 by means of a first seal 210 which is, for example, a butyl seal. The outward facing sides of the spacers 208 are sealed by means of a second seal 212 which is, for example, a polysulfone seal.
For supplying a driving signal, the switchable optical device 10 comprises metal contact sheets 68 which are contacted by the spring contact 220. In the embodiment of
In the embodiment of
A controller may be used to generate driving signals for the switchable optical device. The controller may be connected to the electrical connectors 316.
The window 300 comprises a window frame 310 and an insulated glazing unit having a first pane 202, and a second pane 206.
For retro-fitting of the window 300, a window element 100 and mounting elements 400 are provided. In a first step, the mounting elements 400 are attached to the first pane 202 of the insulated glazing unit of the existing window 300. The mounting elements 400 may, for example, be attached by means of an adhesive. In a second step, the switchable glazing unit 200 is formed by attaching the window element 100 to the mounting elements 400, for example by means of connecting elements such as screws or by means of an adhesive. The window element 100 as shown in
In the example depicted in
The existing window 300 comprises a window frame 310 and an insulated glazing unit having a first pane 202, a second pane 206 and spacers 208. The insulated glazing unit is supported in the window frame 310 by means of a support block 214.
In the example shown in
The switchable optical device 10 comprises metal contact sheets 68 for providing an electrical connection. In the example of
A block 312 and a clamping bar 318 are provided to secure the switchable optical device 10 and to hide non-switchable areas 82 of the switchable optical device 10. The clamping bar 318 is attached to the window frame 310.
The existing window 300 comprises a window frame 310 and an insulated glazing unit having a first pane 202, a second pane 206 and spacers 208. The insulated glazing unit is supported in the window frame 310 by means of a support block 214. On the surface of the second pane 206 which faces inwards towards the first pane 202, a low-e coating 203 is arranged.
In the example shown in
A clamping bar 318 is provided to secure the first holder 216 and to hide non-switchable areas 82 of the switchable optical device 10. The clamping bar 318 is attached to the window frame 310.
The switchable optical device 10 of
In the example shown in
In order to hide the size difference and in addition to hide non-switchable areas 82 of the switchable optical device 10, a passepartout-frame 420 is provided in form of an enlarged clamping bar 318. The clamping bar 318 is attached to the window frame 310.
In
The first holder 216 comprises a recess 260 for receiving the switchable optical device 10. Further, the first holder 216 comprises a spring contact 220 for engaging the metallized surface 48. A further spring contact 220′ is arranged to contact the film heater 62. Additionally, the first holder 216 as depicted in
A further spring contact 220′ is arranged to contact a film heater 62 of the switchable optical device. Additionally, the first holder 216 as depicted in
| Number | Date | Country | Kind |
|---|---|---|---|
| 19183887.9 | Jul 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/068182 | 6/29/2020 | WO |
