WO2014057267A1

WO2014057267A1 - Electromagnetic radiation permeable glazing with a sign

Info

Publication number: WO2014057267A1
Application number: PCT/GB2013/052632
Authority: WO
Inventors: Stephen Roland Day
Original assignee: Pilkington Group Limited
Priority date: 2012-10-10
Filing date: 2013-10-09
Publication date: 2014-04-17
Also published as: GB201218182D0

Abstract

A glazing comprising: at least one transparent substrate coated with an electrically conductive layer, wherein the electrically conductive layer is absent in one or more regions such that said regions allow the passage of electromagnetic radiation and at least a portion of said regions form at least one sign, wherein said regions are arranged to allow the passage of electromagnetic radiation that corresponds to very high frequencies (30-300 MHz, 10 m-1 m), ultra high frequencies (300-3000 MHz, 1 m-100 mm), and/or super high frequencies (3-30 GHz, 100 mm-10 mm) only.

Description

Electromagnetic radiation permeable glazing with a sign

The present invention relates to a glazing with an electrically conductive layer that forms a sign that is permeable to electromagnetic radiation. The invention also relates to a glazing assembly, a door and a building incorporating said glazing; a method of preparing said glazing; a method of transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside a building, when located inside said building; a method of evacuating at least one person from a building; and the use of said glazing.

It is known in the art to provide glazings with electrically conductive layers to reduce the transmission of IR through windows. It is also known that these conductive coatings significantly attenuate the propagation of radio waves and microwaves. The attenuation of radio and microwave communication signals is typically an unwanted side effect of these electrically conductive layers. By removing some selected parts of these conductive layers, radio and microwave communication can be restored. For example, US 5867129 mentions a window with an electrically conductive layer which, while shielding against electromagnetic radiation of long wavelengths and reflecting infrared radiation, allows microwaves to pass through. This is achieved by the electrically conductive layer containing at least one slit whose length is a function of the wavelength of microwave radiation. Preferably in this example the slits are not visible with the naked eye as they would be a distraction to the vehicle driver. These conductive coatings do interact with visible light and it is practically impossible to remove them in a way that the removal cannot be noticed by the human eye. The removal may be noticed because the light transmission is varied or the glazing colour is varied.

It is known that many glass coatings are created from multiple layers of different composition. It is common that each layer will have a precisely computed thickness and refractive index so that as far as is practical the conductive coating as a whole is visibly transparent and neutrally coloured. Deletion or omission of a part of the conductive coating has the effect that the boundaries between coated and uncoated areas can become particularly noticeable to the eye because these precise layer thicknesses become locally disturbed on the boundary of the etching or selective deposition of the coating. US 5620799 describes a glazing with good transmissivity in a particular area for a part of the electromagnetic spectrum that allows data to be transmitted. Over the rest of the surface the same radiation is prevented from passing through by being reflected and/or absorbed. The glazing may have a metallic coating and has a transmitter and/or receiver in said area. To mitigate the effect of the area being distinguishable from the rest of the glazing with the naked eye, and to give the glazing a homogeneous appearance, the glazing may be selectively tinted to a darker optical shade. It is common practice in automotive glass design to tint the glazing across the upper edge of the windscreen to reduce solar glare to the vehicle occupants. US 5620799 makes the point that the area created for data transmission is less visually noticeable when it is in the tinted glazing area. It also highlights that the tinting shade can be variable and be particularly intense in the region of the data transmission area.

EP 0717459 describes a glazing with a metallic layer that has a pattern in the form of a grid of spacings in the layer arranged to allow microwaves and electromagnetic radiation of longer wavelength to pass through. A planar aerial for microwave reception may be disposed behind the grid. The width of the grid lines cut into the conductive coating by laser is described as 0.1mm - 0.05mm so that they are optically relatively difficult to visually detect.

Modern society expects easy use of mobile phones and other devices particularly when the user is stood in proximity to a window that gives a visual view of the outside world. If this window is a solar IR controlling window then such a location is generally poor for radio and microwave transmission and reception. Omitting the conductive coatings on all building or vehicle glazings would typically cause unacceptable IR heat loss or gain. In emergency situations such as a fire it is expected that members of the public would need to alert emergency services to the predicament. A common method of communication that would likely be attempted is the use of mobile phones.

It would be beneficial to provide some glazings with an electrically conductive layer that allows the passage of electromagnetic radiation, that is also easily identifiable as, for example, a particular type of glazing such as a glazing that is permeable to electromagnetic radiation.

According to a first aspect of the present invention there is provided a glazing comprising: at least one transparent substrate coated with an electrically conductive layer, wherein the electrically conductive layer is absent in one or more regions such that said regions allow the passage of electromagnetic radiation and at least a portion of said regions form at least one sign,

wherein said regions are arranged to allow the passage of electromagnetic radiation that corresponds to very high frequencies (30-300 MHz, 10 m-1 m), ultra high frequencies (300- 3000 MHz, 1 m-100 mm), and/or super high frequencies (3-30 GHz, 100 mm-10 mm) only.

The glazing according to the present invention offers distinct advantages over the prior art since whilst it provides the benefits of an electrically conductive layer, which may be used to reduce the transmittance of solar radiation, and affords some permeability to electromagnetic radiation such as mobile or cellular phone signals, it additionally utilises the permeable regions to form a sign which can indicate e.g. the type of glazing, such as a glazing permeable to mobile phone signals, and/or a fire exit etc. This arrangement enables a person to easily identify a glazing that allows the passage of electromagnetic radiation and therefore may be used for instance in an emergency as a location through which emergency services can be contacted via a mobile phone and possibly as a route for emergency services to access a building.

The present invention has clear advantages over signs that are affixed to glazings for example by an adhesive. For instance, unlike a sign stuck to a window, the sign formed as part of the glazing of the present invention does not degrade under environmental influences, cannot be removed easily through an act of vandalism unless the glazing itself is broken, and ensures that there is an unobstructed view through the glazing. Furthermore, the glazing of the present invention of course provides the additional benefits associated with its permeability to electromagnetic radiation.

In the following discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

In the context of the present invention a transparent material is a material that is capable of transmitting visible light so that objects or images situated beyond or behind said material can be distinctly seen through said material.

Preferably the electrically conductive layer is transparent. This arrangement enables an observer to have a distinct view through the entire glazing. Preferably the transmitted light through the transparent substrate is different from the transmitted light through the transparent substrate coated with the electrically conductive layer. Preferably the reflected light from the transparent substrate is different from the reflected light from the transparent substrate coated with the electrically conductive layer. Such arrangements provide an observer with a distinct view through the entire glazing and a visibly perceptible distinction between the coated and uncoated regions. This visible distinction may be apparent under normal light conditions such as daylight and/or artificial light sources. The distinction between the coated and uncoated regions may have the appearance of a watermark effect which is both unobtrusive and readily apparent.

The glazing may have both transparent regions and non-transparent regions e.g. opaque regions. Preferably the glazing is substantially completely transparent. Preferably at least 80%, more preferably at least 90%, and even more preferably at least 95% of the glazing is transparent when viewed through a major surface of the glazing, wherein the entire surface area of said major surface is deemed to represent 100% of the glazing for the purposes of these values. Most preferably the glazing is completely transparent.

Preferably said regions where the electrically conductive layer is absent are arranged to allow the passage of electromagnetic radiation that corresponds to ultra high frequencies and/or super high frequencies only and more preferably electromagnetic radiation that corresponds to frequencies at which only mobile phones or cellular phones, and/or devices that can wirelessly connect to the internet, function. Preferably the perimeter length of at least one of the regions in which the electrically conductive layer is absent is at least 5 mm in length, more preferably at least 50 mm in length, even more preferably at least 200 mm in length, but preferably at most 10 m in length, more preferably at most 2 m in length, even more preferably at most 1 m in length. Human vision will tend to notice a sign more as the areas of the regions in which the electrically conductive layer is absent increases, but the transmission of radio frequency may require the perimeter length of one or more said regions to be approximately the wavelength of the lowest radio frequency that can be transmitted through said regions. It is well known in slot antenna design and frequency selective surface, F.S.S., design that a region in which an electrically conductive layer is absent can be made to pass lower radio frequencies if the perimeter of said regions is formed into a convoluted shape with a longer perimeter length.

Preferably the sign, which itself may be repeated multiple times, has a longest dimension of at least 10 cm, more preferably at least 20 cm, even more preferably at least 30 cm. Preferably the sign has a shortest dimension of at least 1 cm, more preferably at least 10 cm, even more preferably at least 15 cm. Preferably the sign has a minimum surface area of 5 cm², more preferably 50 cm², even more preferably 450 cm². The minimum dimensions set out in this paragraph aid the visibility of the sign to the naked eye of a viewer.

Preferably the electrically conductive layer coats at least 50% of a surface of a transparent substrate, more preferably at least 80% and most preferably at least 95%.

Preferably the electrically conductive layer has a resistance of less than 1000 Ohms per square, more preferably less than 300 Ohms per square and even more preferably less than 50 Ohms per square.

Preferably the sign indicates that the glazing allows the passage of electromagnetic radiation, more preferably radio and microwave frequency radiation, even more preferably electromagnetic radiation at frequencies at which mobile phones or cellular phones function e.g. by incorporating a symbol of a mobile phone and/or words such as "mobile phone compatible". In some preferred embodiments the sign indicates that the glazing allows the passage of electromagnetic radiation at frequencies at which devices that can wirelessly connect to the internet function e.g. by incorporating a Wi-Fi symbol (see Figure 6). Such a sign enables a viewer to instantly recognise that a particular glazing can be used to transmit and receive signals in the event of an emergency or otherwise.

Alternatively, or additionally, the sign may indicate that the glazing, or a door in which the glazing is incorporated, can be used as a fire escape/fire exit and/or a route for emergency services to access a building e.g. by incorporating a symbol that indicates a fire escape/exit such as the symbol of a running person or an exclamation mark, depicting an access point for emergency services, and/or incorporating words such as "fire escape", "fire exit" or "emergency access". This arrangement is advantageous because it enables a viewer to immediately identify a glazing or a door incorporating such a glazing, which could be crucial in the event of an emergency such as a fire in order that occupants trapped in a building can be evacuated as quickly as possible.

In a preferred arrangement the sign indicates that the glazing allows the passage of electromagnetic radiation, such as UFIF radiation, and also indicates that the glazing, or a door in which the glazing is incorporated, can be used as a fire escape/fire exit and/or a route for emergency services to access a building. This combination is beneficial because it enables an occupant of a building to quickly locate a glazing where emergency services can be contacted via a mobile phone and directed to the glazing in order that the occupant can be evacuated.

Signs that have an obvious visual meaning to a building occupant may typically have several different shaped regions where the conductive layer is absent. Preferably the regions in which the electrically conductive layer is absent are large enough to be read and/or comprehended with unaided human eyesight. The designer of a sign will typically have artistic freedom to choose may shapes of region that still convey the same meaning. A designer of signs according to this invention may typically employ radio frequency computer simulation or radio frequency testing to determine regions and perimeter shapes that are particularly advantageous for the intended communication frequencies. The designer of a sign according to this invention may also be interested in avoiding excessive regions in which the conductive layer is absent where the primary purpose of said regions is solar and heat control. Preferably the regions in which the electrically conductive layer is absent are arranged in a repeating pattern such that there is repetition of the sign. Such an arrangement may enhance the visibility of the signs. It is known in the field of F.S.S., e.g. in WO03047030, to repeat the same patterns of conductor at specific intervals. The field of F.S.S. typically describes relatively simple geometric boundaries between conductive and non-conductive material but the principle of optimising the periodic spacing of a pattern can also be applied when that pattern is a graphical symbol or a sign.

Any coating aperture will have resonant frequencies where it is specifically good at allowing radiation transmission. In fact even the simplest slot shapes, e.g. in US 5867129, will preferentially pass a series of frequencies the lowest of which will correspond to the slot length being ½ (half) wavelength long and the next 3/2 wavelengths long. Aperture shapes in the field of F.S.S. have been formulated that can pass and reject several different frequencies.

Any graphical symbol or sign chosen can be tested for its radio transmission properties and optimised in scale so that one or more preferred frequencies, e.g. the different frequencies used by mobile phones, are the resonant frequencies. A change of scale will typically tune one frequency and there will be benefit from testing a range of forms of sign with the same meanings but different resonant frequencies to get a good solution where transmission at more than one radio frequency is important.

The selective deposition of coatings or removal of coatings, e.g. by laser, is a relatively specialised job requiring specialist equipment. It may be common for a glazier to be unable to specify sufficiently in advance of glazing manufacture which position on a glass sheet the identifiable symbol or sign should occur. For this situation the glazing manufacturer can manufacture typically smaller signs arranged in an optimised regular and periodic way using the knowledge and techniques from the field of F.S.S. Glazings made in this way would typically have many repeating copies of the sign within a single window or door aperture.

Lighting effects may be used to enhance the visibility of the sign. The glazing may further comprise one or more light such as an electrically powered light. Said one or more light may preferably be situated at the perimeter of the glazing. The light may be attached, directly or indirectly, to an external surface of the glazing or the light may be located inside the glazing, for instance the light may be laminated inside the glazing. The light may comprise an LED component or LED device which may be deposited onto a substrate such as a plastic film or a glass surface or laminated between substrates. Alternatively, the light may comprise one or more electroluminescent materials formed onto a substrate. Where the light is an electrically powered light, one or more conductors may be formed from an electrically conductive layer wherein said layer does not entirely block the passage of electromagnetic radiation through the glazing in the region of the sign.

Printing or other such effects may be used to enhance the visibility of the sign. The glazing may further comprise one or more paints and/or inks. Said paints and/or inks may be aligned with the sign. Said paints and/or inks may be coloured, opaque and/or optically diffuse. Said paints and/or inks may be electrically conductive or non-conductive, wherein said paints and/or inks do not entirely block the passage of electromagnetic radiation through the glazing in the region of the sign. Said paints and/or inks may be printed onto the glazing.

Materials and coatings that can switch light transmission through the substrates in some way may be used to enhance the visibility of the sign. For instance the glazing may further comprise one or more electrically switchable material that can reversibly affect the light transmission through the glazing, such as electrochromic and/or light scattering LCD materials. Said electrically switchable materials may be arranged to switch using an electrically conductive layer, in which case said layer does not entirely block the passage of electromagnetic radiation through the glazing in the region of the sign.

Said lights and/or electrically switchable materials may be arranged to be activated or deactivated as required. This functionality enables a more obvious visibility of the sign during events appropriate to the meaning of the sign.

Glazings according to the present invention may be coated with numerous types of thin coatings. The electrically conductive layer may comprise multiple layers of material. Some or all of said layers of material may exhibit a different conductivity from each other. The thickness of the conductive layers of these materials affects their blocking of radio and other frequency communication. Due to the electrically conductive layers generally being thin in comparison to the wavelengths of radio frequencies it is most convenient to describe the resistivity of coatings in the unit Ohms per Square. Glazings with electrically resistive layers of higher than 1000 Ohms per square will generally be regarded as not significantly blocking radio frequency transmission. Glazings with electrically resistive coatings made of currently known conductive materials less than 0.1 Ohms per square have very poor light transmission. Typical glazings used for solar control in buildings have resistivities in the range of 50-1 Ohms per square. Conductive glazing coatings do exist that have deliberately poor optical transmission and high optical reflectivity. These glazings might be more commonly described as mirrors and one way mirrors but it will be appreciated that they can be used in the door and window apertures of buildings as a substitute for more transparent forms of glazing.

The electrically conductive layer may comprise conductive particles, fibres and/or wires of dimensions smaller than the unaided human eye can resolve. For example, the electrically conductive layer may comprise nano-particles and/or nano-wires. So called nano-particles and nano-wires have such small dimensions that they can electrically connect to form solar control coatings that are electrically conductive on a scale large enough to block radio frequency transmission.

Preferably the at least one electrically conductive layer contains metals, conductive organic polymers, conductive forms of carbon, and/or metal oxides made substantially conductive by doping. Particularly important examples of solar control electrically conductive layer materials include silver, copper, gold, aluminium, tin oxide, indium oxide and zinc oxide. The electrically conductive layer may decrease the emissivity ("low-e coating") of the glazing to achieve thermal insulation properties by reflecting the infrared radiation emitted by for instance the interior of a building, and/or to reduce its solar energy transmittance ("solar control coating") to shield interior rooms against the entry of excessive amounts of solar energy (heat). The electrically conductive layer may be a layer system with at least one transparent silver-based layer that follows the structure: glass/lower antireflection layer/silver-based layer/outer antireflection layer. In layer systems of this type, the silver layer serves mainly as an IR reflection layer, whilst the anti-reflection ("AR") layers may be employed, through suitable selection of material and thickness, to influence the transmission and reflection properties in the visible region of the spectrum, emissivity and solar energy transmittance, according to application.

In the context of the present invention, where a layer is said to be "based on" a particular material or materials, this means that the layer predominantly consists of said material or materials, which means typically that it comprises at least about 50 wt.% of said material or materials.

Preferably the at least one transparent substrate is at least one glass ply. The at least one transparent substrate is preferably more than 1% light transparent and more preferably more than 10% light transparent. The transparent substrate may be more transparent at some optical wavelengths than others. The transparent substrate may be coloured by the effect of different optical transmissions to different coloured light. This arrangement may make the sign more visible. Examples of tinted glass for glazing include the Pilkington Optifloat (RTM) range of glass that includes green, bronze, grey and blue tints. Another example is Pilkington Optiwhite (RTM).

Preferably the substrate and/or the electrically conductive layer is coloured and/or incorporates one or more light scattering materials. The use of coloured or light scattering materials in the substrate and/or the electrically conductive layer enhances the visibility of the sign.

Preferably the at least one substrate is a coated glass from which the coating has been partially removed to form the sign. Alternatively the at least one substrate is a coated glass manufactured using a process that prevents the deposition of the electrically conductive layer in the regions of the sign. Examples of coated glass include Pilkington Optitherm (RTM) glass and TEC 15 (RTM) glass.

Preferably the glazing comprises at least two transparent substrates. Preferably the electrically conductive layer is located between said at least two transparent substrates. Said at least two transparent substrates may be separated by a gap. Where a substrate is coated with an electrically conductive layer, said layer does not entirely block the passage of electromagnetic radiation through the glazing in the region of the sign. In some preferred embodiments the glazing incorporates at least two electrically conductive layers, wherein said layers do not entirely block the passage of electromagnetic radiation through the glazing in the region of the at least one sign.

In an alternative embodiment at least one ply of an interlayer material may be laminated between the at least two transparent substrates. The interlayer material may be selected from the group consisting of polyvinyl butyral (PVB), Ethylene- Vinyl Acetate (EVA), polyethylene terephthalate (PET) and other polymeric interlayers. An interlayer may comprise an electrically conductive layer. Said electrically conductive layer may coat a surface of a ply of interlayer material and/or said layer may be laminated between at least two plies of an interlayer material. Where a ply of interlayer material comprises an electrically conductive layer said layer does not entirely block the passage of electromagnetic radiation through the glazing in the region of the sign.

Preferably the glazing comprises at least two transparent substrates, wherein the substrates are separated by a gap and/or at least one ply of an interlayer material is laminated between the substrates.

The glazing may be a fire resistant glazing. When the glazing is a fire resistant glazing, the interlayer material may be a transparent intumescent material comprising an alkali metal silicate and water.

According to another aspect of the present invention there is provided a glazing assembly comprising at least one glazing according to the present invention attached to a frame. The frame may comprise any suitable surround that supports the glazing such as a window frame and/or a door.

According to another aspect of the present invention there is provided a door incorporating at least one glazing according to the present invention. According to another aspect of the present invention there is provided a building incorporating at least one glazing according to the present invention.

According to a further aspect of the present invention there is provided a method of preparing a glazing according to the present invention comprising:

coating at least one transparent substrate with an electrically conductive layer,

wherein either the electrically conductive layer is deposited through a mask and/or is partially removed after deposition of the electrically conductive layer.

The partial removal of the electrically conductive layer may be conducted using chemical, laser and/or sandblasting means. The chemical means may comprise removal with a concentrated solution of hydrofluoric acid.

According to another aspect of the present invention there is provided a method of transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside a building, when located inside said building, comprising at least the following steps in sequence:

i) identifying a sign on and/or in a glazing in accordance with the present invention;

ii) positioning a mobile phone within at most a 10 m radius of said glazing; and iii) transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside said building with said mobile phone.

Preferably in step ii) the mobile phone is positioned within at most a 5 m radius of said glazing, more preferably at most a 2 m radius of said glazing.

According to another aspect of the present invention there is provided a method of evacuating at least one person from a building comprising said person carrying out at least the following steps in sequence:

ii) positioning a mobile phone within at most a 10 m radius of said glazing; iii) transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside said building with said mobile phone to direct an evacuator to the location of said glazing; and

iv) being evacuated by said evacuator.

Preferably the evacuator is a member of the emergency services, such as a fireperson.

Preferably the at least one person is evacuated via the glazing or via a door incorporating said glazing. If the at least one person is evacuated via the glazing, the glazing may be smashed to allow evacuation or, if the glazing is openable, the glazing may be opened to allow evacuation.

According to another aspect of the present invention there is provided the use of a glazing in accordance with the present invention to allow the transmission of mobile phone signals to and/or reception of signals from an aerial at a location outside a building, when located inside said building.

Preferably the use of said glazing is to facilitate the evacuation of a building.

It will be appreciated that optional features applicable to one aspect of the invention can be used in any combination, and in any number. Moreover, they can also be used with any of the other aspects of the invention in any combination and in any number. This includes, but is not limited to, the dependent claims from any claim being used as dependent claims for any other claim in the claims of this application.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention will now be further described by way of the following specific embodiments, which are given by way of illustration and not of limitation, with reference to the accompanying drawings in which:

Fig. 1 shows a glazing in accordance with the present invention incorporating a sign depicting a mobile phone;

Fig. 2 shows a glazing in accordance with the present invention incorporating signs depicting a mobile phone and a fire exit/escape;

Fig. 3 shows a glazing in accordance with the present invention incorporating signs depicting a mobile phone and an access point for emergency services;

Fig. 4 shows a door in accordance with the present invention incorporating a glazing with signs depicting a mobile phone and a fire exit/escape;

Fig. 5 shows a glazing in accordance with the present invention incorporating several signs depicting a mobile phone in a repeating pattern; and

Fig. 6 shows a glazing in accordance with the present invention incorporating a Wi-Fi sign.

Fig. 1 shows a front view of a glazing 1 according to the present invention comprising two glass plies 2 (only one ply is visible) with a ply of interlayer material (not shown) laminated between said plies. The glazing 1 is a fire resistant glazing in which the interlayer material is a transparent intumescent material composed of an alkali metal silicate and water. An electrically conductive layer 3 coats one of the glass plies 2. The electrically conductive layer is located between the two glass plies 2 and is a transparent silver-based layer. The electrically conductive layer 3 is absent in the region 4 (here coloured black) which forms a sign depicting a mobile phone, indicating that the glazing 1 can be used to transmit and receive signals in the event of an emergency or otherwise. In this case the region 4 is arranged to allow the passage of electromagnetic radiation that corresponds to frequencies at which mobile phones function.

Fig. 2 shows a front view of a glazing 1 according to the present invention that is the same as the glazing 1 shown in Fig. 1 but additionally incorporates region 5 (coloured black) in which the electrically conductive layer 3 is absent and which forms a sign depicting a fire exit/escape.

Fig. 3 shows a front view of a glazing 1 according to the present invention that is the same as the glazing 1 shown in Fig. 1 but additionally incorporates region 6 (coloured black) in which the electrically conductive layer 3 is absent and which forms a sign depicting an access point for emergency services.

Fig. 4 shows a front view of a door 7 according to the present invention that incorporates a glazing 1 according to the present invention. The glazing 1 is the same as the glazing 1 shown in Fig. 2.

Fig. 5 shows a glazing 1 in accordance with the present invention that is the same as the glazing shown in Fig 1 except that the electrically conductive layer 3 is absent in several regions 4 (here coloured black) arranged in a repeating pattern such that there is repetition of a sign depicting a mobile phone i.e. similar to a wallpaper design.

Fig. 6 shows a front view of a glazing 1 according to the present invention that is the same as the glazing 1 shown in Fig. 1 except that a sign depicting a mobile phone is not present and instead the electrically conductive layer 3 is absent in the region 8 (here coloured black) which forms a Wi-Fi sign, indicating that the glazing 1 can be used to transmit and receive wireless internet signals in the event of an emergency or otherwise.

The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A gl azing compri sing :

at least one transparent substrate coated with an electrically conductive layer,

wherein the electrically conductive layer is absent in one or more regions such that said regions allow the passage of electromagnetic radiation and at least a portion of said regions form at least one sign,

2. The glazing according to claim 1, wherein the electrically conductive layer is transparent.

3. The glazing according to claim 1 or claim 2, wherein the transmitted and reflected light from the transparent substrate is different from the transmitted and reflected light from the transparent substrate coated with the electrically conductive layer.

4. The glazing according to any preceding claim, wherein said regions are arranged to allow the passage of electromagnetic radiation that corresponds to ultra high frequencies only.

5. The glazing according to any preceding claim, wherein the perimeter length of at least one of the regions in which the electrically conductive layer is absent is at least 10 mm in length, but at most 1 m in length.

6. The glazing according to any preceding claim, wherein the sign has a minimum surface area of 50 cm².

7. The glazing according to any preceding claim, wherein the sign indicates that the glazing allows the passage of electromagnetic radiation at frequencies at which mobile phones or cellular phones, and/or devices that can wirelessly connect to the internet, function.

8. The glazing according to any preceding claim, wherein the sign incorporates a symbol of a mobile phone.

9. The glazing according to any preceding claim, wherein the sign indicates that the glazing, or a door in which the glazing is incorporated, can be used as a fire escape/fire exit and/or a route for emergency services to access a building.

10. The glazing according to any preceding claim, wherein the regions in which the electrically conductive layer is absent are arranged in a repeating pattern such that there is repetition of the sign.

11. The glazing according to any preceding claim, wherein the glazing further comprises one or more light and/or one or more electrically switchable material that can reversibly affect the light transmission through the glazing.

12. The glazing according to any preceding claim, wherein the glazing further comprises one or more paints and/or inks.

13. The glazing according to any preceding claim, wherein the substrate and/or the electrically conductive layer is coloured and/or incorporates one or more light scattering materials.

14. The glazing according to any preceding claim, wherein the glazing comprises at least two electrically conductive layers, wherein said layers do not entirely block the passage of electromagnetic radiation through the glazing in the region of the at least one sign.

15. A glazing assembly comprising at least one glazing according to any of claims 1 to 14 attached to a frame.

16. A method of preparing a glazing according to any of claims 1 to 14 comprising:

coating at least one transparent substrate with an electrically conductive layer, wherein either the electrically conductive layer is deposited through a mask and/or is partially removed after deposition of the electrically conductive layer.

17. A method of transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside a building, when located inside said building, comprising at least the following steps in sequence:

i) identifying a sign on and/or in a glazing in accordance with any of claims 1 to 14; ii) positioning a mobile phone within at most a 10 m radius of said glazing; and iii) transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside said building with said mobile phone.

18. A method of evacuating at least one person from a building comprising said person carrying out at least the following steps in sequence:

i) identifying a sign on and/or in a glazing in accordance with any of claims 1 to 14; ii) positioning a mobile phone within at most a 10 m radius of said glazing;

iii) transmitting mobile phone signals to and/or receiving signals from an aerial at a location outside said building with said mobile phone to direct an evacuator to the location of said glazing; and

iv) being evacuated by said evacuator.