HIGHLY SECURE PANEL OF LAMINATED GLASS

The invention relates to a panel of laminated glass with a first glass substrate, a second glass substrate and an electronic component.

Technical Background

Laminated glass is a type of safety glass that holds together when shuttered. In the event of breaking, broken glass pieces are held in place by a plastics interlayer, typically of Polyvinylbutyral (PVB), between its two or more layers of glass substrates. The plastics interlayer keeps the layers of glass substrates bonded even when broken, and its high strength prevents the glass substrates from breaking-up into free sharp pieces.

Methods for manufacturing laminated glass are well-known in the window in- dustry since decades. A so-called sandwich of the first glass substrate, the plastics interlayer and the second glass substrate is laminated in an automated laminating line by using the procedure of calendaring and autoclaving. Calendaring means the pre-gluing of the sandwich under the action of a pressure imposed by two rolls applied on either side of the glass substrates. The final gluing of the glass substrates by a vacuum/heating cycle, which combines pressure and temperatures, takes place during the step of autoclaving, which removes air between the plastics interlayer and the glass substrates.

Such a laminated glass can be used as a heating window pane comprising a heating layer for automotive application such as described in document US7301126B2 in which a solution to prevent the propagation of the corrosion of the heating layer from the edge to the center of the pane is described.

In the building, decoration, automotive, aviation and other industries, panels of laminated glass with integrated electronic components, such as light emitting diodes

(LED), are known, e.g. for displaying information or for lighting purposes. For these application areas, the manufacturing of a panel of laminated glass with electronic com- ponents typically comprises the steps of depositing a conducting layer on the first layer

of glass substrate, forming conductive paths and patterns in the conductive layer and depositing of electronic components on the conducting layer, connected to the conductive paths. The plastics interlayer is then deposited on the conducting layer. The sandwich is obtained by the application of the second layer of glass on the plastics inter- layer, which is then laminated as outlined before.

EP 1 437 215 describes such a panel of laminated glass with at least two glass substrates and one or more plastic interlayers, such as PVB, in which the electronic components as well as their connecting circuits are formed between the two glass substrates, wherein the connecting circuits are formed from at least one conductive layer. In this way, the conductive layer is not accessible to an operator, as it is protected by at least two insulating materials, which are typically at least the plastics interlayer and a glass substrate. Further, electrical power applied to the conductive layer of the panel of laminated glass of EP 1 437 215 or to other panels of laminated glass known from the prior art is typically applied at below 48 V and therefore not dangerous for the operator.

However, with respect to to deployment of greater electrical power, such as an electrical potential exceeding 200 V, to a panel of laminated glass integrating electronic components requiring more and more power (particularly for lighting applications), the insulation is no longer sufficient as far as security is concerned. In fact, the slightest defect of the plastics interlayer could create a source of electrical danger for the operator of the panel of laminated glass.

Summary of the Invention

Accordingly, it is the object of the invention to provide a panel and method of making a panel of laminated glass integrating electronic component(s) that can be safely operated. An advantage of the present invention is a laminated panel integrating elec- tronic component(s) operating at a greater electrical power and, further, minimizing the source of electrical danger for the operator of the panel of laminated glass.

This object is addressed by a panel of laminated glass, comprising an inner conductive layer provided between a first glass substrate and a second glass substrate, and an electronic component in electrical contact with the inner conductive layer, wherein the inner conductive layer is only provided in an inner region of the panel of laminated glass.

Accordingly, it is an essential idea of the invention to provide the inner conductive layer only in an inner region of the panel of laminated glass, which means that the inner conductive layer is distant from an outer border of the panel of laminated glass. There is a non-conductive zone somewhere between the outer border or borders of the conductive layer and the outer edges of the glass panel. This non-conductive zone provides a better insulation. This is advantageous, since, when applying electrical power to the inner conductive layer, the invention assures security for the operator touching the outer border of the panel of laminated glass. Accordingly, the electrical power applied to the inner conductive layer is not a source of electrical danger anymore at the outer border of the panel of laminated glass anymore. Accordingly, higher voltages can be used.

According to a preferred embodiment of the invention, the inner conductive layer is surrounded by an outer conductive layer, wherein the inner conductive layer is electrically separated from the outer conductive layer. This means, that e.g. during manufacturing of the panel of laminated glass, a preferably common conductive layer is first provided on the entire first glass substrate and then separated into an inner conductive layer and an outer conductive layer. In this way, when applying electrical power to the inner conductive layer, due to the electrical separation between the inner conductive layer and the outer conductive layer, there is no electrical contact from the inner con- ductive layer to the outer conductive layer. Accordingly, electrical power is not present in the outer conductive layer, e.g. when the outer conductive layer is touched by an operator. Such an embodiment is advantageous, since the panel of laminated glass can be manufactured with existing manufacturing methods, as described further above. For the

terms "electrical separation" and "electrically separated", respectively, it should be understood to mean "ohmically or galvanically isolated".

In general, the inner conductive layer can be electrically separated from the outer conductive layer by any manufacturing method. For example, during manufacturing the inner conductive layer is first provided on the first glass substrate, e.g. by a suitable deposition technique, and then afterwards the outer conductive layer is provided on the first glass substrate e.g. by a suitable deposition technique. However, according to a preferred embodiment of the invention, the inner conductive layer is electrically separated from the outer conductive layer by a zone in which the deposited conductive layer has been removed, i.e. by the formation of a groove or isolation zone in the conductive layer. Preferably, during manufacturing the conductive layer is provided on the first glass substrate and is then electrically separated by a laser beam, e.g. by laser ablation, or any other comparable tool, into the inner conductive layer and into the outer conductive layer. In this way, the isolation zone or groove is provided by the laser beam. Pref- erably, the isolation zone or groove is some tens of microns in width, preferably 50 μm to 100 μm. The electrical separation by a laser beam, e.g. by laser ablation, is applicable for different types of conductive layers known from the prior art, wherein the conductive layer is for example applied by a sputtering magnetron or chemical vapor deposition.

According to another preferred embodiment of the invention, the inner conductive layer runs parallel to an outer border of the panel of laminated glass. It is further preferred, that the inner conductive layer runs parallel to the entire outer border of the panel of laminated glass. In other words, the inner conductive layer is surrounded by an insulating and parallel margin, such as the outer conductive layer, wherein the inner conductive layer is electrically insulated from the outer border of the panel of laminated glass.

Accordingly, it is especially preferred that the inner conductive layer is at least 5 mm distant from the outer border of the panel of laminated glass. In this way, the outer conductive layer is preferably 5 mm wide. Such a width of 5 mm allows for sufficient

electrical insulation of the outer border of the panel of laminated glass, even when applying electrical power of 200 V or more to the inner conductive layer.

According to a further preferred embodiment of the invention, the inner conductive layer and the outer conductive layer are co-extensive or congruent with the panel of laminated glass. This means that preferably the entire size of the panel of laminated glass or of the first glass substrate, respectively, is covered with a common conductive layer, which is electrically separated into the inner conductive layer and into the outer conductive layer.

According to a further preferred embodiment of the invention, a plastics inter- layer is provided between the first and a second glass substrate, wherein the first glass substrate and the second glass substrate are laminated together with the plastics inter- layer in between. In general, the plastics interlayer can comprise a plastic foil or a plastic sheet. Preferably, the plastics interlayer comprises Polyvinylbutyral (PVB). If the plastics interlayer is not transparent when applied, it can become transparent after lami- nating, i.e. after calendering and autoclaving. Further, a thermoplastic material such as polyurethane is preferably used as a plastics interlayer.

In general, any kind of electronic components, e.g. passive components such as resistors, capacitors or inductors or active components such as transistors, switches, microprocessors, diodes, modems, or other active electronic elements, can be in electri- cal contact with the inner conductive layer. However, according to a preferred embodiment of the invention, the electronic components comprise at least one light emitting diode (LED). Preferably, the electronic components are provided on the inner conductive layer and/or are located in between the panels of laminated glass. It is further preferred, that the electronic component is fixed to at least an electronic circuit realized in the inner conductive layer, i.e. conductive paths join groups of electronic components together. The electronic circuits or conducive paths can be realized by previously patterning the first glass plate with the inner conductive layer and/or by previously removing at least a part of the inner conductive layer deposited on the first glass plate by means of e. g. a laser beam, such as by laser ablation. In addition, electrodes are pref-

erably provided for supplying electrical power to the electronic components via the electronic circuits. Preferably, a plurality of electronic circuits is provided, wherein each circuit connects to an LED or a plurality of LEDs, e.g. in different colours. Preferably, the electronic component and/or the LEDs are electrically connected to the inner con- ductive layer by means of glueing, e. g. with conducting glue, and/or by soldering.

The object of the invention is further addressed by a method for manufacturing a panel of laminated glass, comprising the steps of providing a conductive layer on a first glass substrate, electrically separating the conductive layer into an inner conductive layer and an outer conductive layer, equipping the inner conductive layer with an elec- tronic component, wherein the electronic component is in electrical contact with the inner conductive layer, and providing a second glass substrate, wherein the conductive layer is provided between the first glass substrate and the second glass substrate.

In other words, a panel of laminated glass can be manufactured according to the method of the invention, wherein the conductive layer is separated into an inner conduc- tive layer and an outer conductive layer, and wherein the method further comprises the step of equipping the inner conductive layer with an electronic component. This is advantageous, since the method according to the invention improves security, especially when applying greater electrical power to the inner conductive layer, as the outer conductive layer, which is tangible at the border of the panel of laminated glass by an op- erator, is electrically separated from the inner conductive layer.

According to a preferred embodiment of the invention, the method further comprises the step of providing an isolation zone or groove in the conductive layer for electrically separating the inner conductive layer from the outer conductive layer. Preferably, the groove is provided by a laser beam, e.g. by laser ablation, and is some tens of microns in with, preferably 50 μm to 100 μm. In this way, the panel of laminated glass can be manufactured with conventional manufacturing methods by applying at least an additional step of providing the groove in the conductive layer for electrically separating the inner conductive layer from the outer conductive layer.

According to a further preferred embodiment of the invention, the method further comprises the step of removing the outer conductive layer from the first glass substrate. In this way, the inner conductive layer is surrounded by an insulating margin.

According to a further preferred embodiment of the invention, the method fur- ther comprises the step of laminating the first glass substrate and the second glass substrate via a plastics interlayer, wherein the plastics interlayer is provided on the second glass substrate. Preferably, the plastics interlayer comprises Polyvinylbutyral.

In any of the embodiments of the present invention the glass panels are at least 0,25 m in size.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

Brief Description of the Drawings

In the drawings:

Fig. 1 schematically shows a panel of laminated glass according to a preferred em- bodiment of the invention in a sectional view, and

Fig. 2 schematically shows the panel of laminated glass according to another preferred embodiment of the invention in a top view.

The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Description of the illustrative embodiments

Where the term "comprising" is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g. "a" or "an", "the", this includes a plural of that noun unless something else is specifically stated.

Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of op- eration in other sequences than described or illustrated herein.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in vari- ous places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodi- ments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Fig. 1 schematically shows a panel of laminated glass 1 in a sectional view according to a preferred embodiment of the invention. The panel of laminated glass 1 comprises a first glass substrate 2 and an inner conductive layer 3 provided between the first glass substrate 2 and a second glass substrate 4. The panel of laminated glass 1 further com- prises a plastics interlayer 5 provided on the second glass substrate 4, wherein the first glass substrate 2 and the second glass substrate 4 are laminated together via the plastics interlayer 5.

As it can be seen further from Fig. 1, the panel of laminated glass 1 comprises an outer conductive layer 6, which is separated from the inner conductive layer 3 by a groove 7. The groove is an electrically isolating zone. The inner conductive layer 3 is distant from an outer border 8 of the panel of laminated glass 1. According to the preferred embodiment of the invention, the inner conductive layer 3 and the outer conductive layer 6 are co-extensive or congruent with the panel of laminated glass l.When applying electrical power to the inner conductive layer 3, the electrical power is not present at the outer border 8 of the panel of laminated glass 1, as the outer conductive layer 6 is electrically separated by the groove 7 from the inner conductive layer 3.

Fig. 2 shows a panel of laminated glass 1 according to another preferred embodiment of the invention in a top view. As it can be seen, the panel of laminated glass 1 comprises the inner conductive layer 3 and the outer conductive layer 6, separated and electrically isolated by the groove 7 from outer conductive layer 6. The groove 7 is distant from the outer border 8 of the panel of laminated glass 1. Further, the inner conductive layer 3 runs parallel to the entire outer border 8 of the panel of laminated glass 1.

As it can be seen further from Fig. 2, a plurality of electronic circuits or conductive paths 9 is realized in the inner conductive layer 3, e.g. by patterning the inner conductive layer 3 during manufacturing, by so-called engraving or removing part of the conductive layer, for example by means of a laser beam. Electronic components 10, such as light emitting diodes (LEDs), are soldered or glued to the electronic circuits 9 realized in the inner conductive layer 3. Other components can also be included e.g. passive components such as resistors, capacitors or inductors or active components such as transistors, switches, microprocessors, diodes, modems, or other active electronic elements. As it can be seen further, electrodes 11, such as bus bars or conducting strips, are realized in the inner conductive layer 3 as well. The electrodes 11 are in electrical contact with the electronic circuits 9. When applying electrical power to the electrodes 11, i.e. that the electrical power is applied to the electronic components 10 connected by the electronic circuits 9 to the electrodes 11, the electrical power is not present on the outer conductive layer 6 and does not provide a source of electrical danger for an opera- tor. Especially when applying greater electrical power to the electrodes 11, such as 200 V or more, the electrical power is not present on the outer conductive layer 6, which means that the outer conductive layer 6 does not provide a source of electrical danger for the operator.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the draw- ings, the disclosure, and the appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.