Glazing with electrically operable light source

Abstract

A laminated glazing comprising first and second panes of glazing material, first and second plies of adhesive interlayer material and an electrical device therebetween is described. The electrical device comprises a substrate having a first major surface and a second opposing major surface wherein on the first major surface of the substrate are one or more electrically conductive pathways in electrical communication with at least one electrically operable light source mounted on the substrate and on at least a portion of the second major surface of the substrate is an infrared radiation reflecting film for reducing the amount of infrared radiation that passes from the second major surface of the substrate to the first major surface of the substrate. An electrical device for use in such a laminated glazing is also described.

Claims

1. A laminated glazing comprising: a first pane of glazing material, a second pane of glazing material, a first ply of adhesive interlayer material, a second ply of adhesive interlayer material and an electrical device, wherein the first and second plies of adhesive interlayer material and the electrical device are between the first and second panes of glazing material; the electrical device is between the first and second plies of adhesive interlayer material and the electrical device comprises 1) a substrate having a first major surface and a second opposing major surface and 2) at least one electrically operable light source mounted on the first major surface; further wherein directly on the first major surface of the substrate are at least two electrically conductive pathways in electrical communication with the at least one electrically operable light source, the at least one electrically operable light source being a first electrically operable light source; and on at least a portion of the second major surface of the substrate is a coating comprising an infrared radiation reflecting film for reducing the amount of infrared radiation that passes from the second major surface of the substrate to the first major surface of the substrate, wherein the coating is in direct contact with the second major surface of the substrate, or is disposed on an intermediate coating on the second major surface of the substrate; and wherein the at least two electrically conductive pathways include a first electrically conductive pathway and a second electrically conductive pathway arranged such that upon electrically connecting the first and second electrically conductive pathways to a power supply, the first electrically operable light source switches on.

2. A laminated glazing according to claim 1, wherein the substrate is monolithic and/or wherein the substrate is optically transparent and/or wherein the substrate comprises a polyester.

3. A laminated glazing according to claim 1, wherein: i) the infrared radiation reflecting film comprises at least one layer comprising a metal; or ii) wherein the infrared radiation reflecting film comprises one or more metallic layers and one or more dielectric layers; or iii) wherein the infrared radiation reflecting film comprises one or more metal oxide layers and one or more dielectric layers; or iv) wherein the infrared radiation reflecting film comprises a plurality of non-metallic layers.

4. A laminated glazing according to claim 1, wherein at least one of the first and second plies of adhesive interlayer material comprises polyvinyl butyral, a copolymer of ethylene, or an ionoplast interlayer material.

5. A laminated glazing according to claim 1, wherein the first electrically operable light source is arranged on the first major surface of the substrate to emit a beam away from the first major surface of the substrate or wherein the first electrically operable light source is arranged on the first major surface of the substrate to emit a beam towards the second major surface of the substrate.

6. A laminated glazing according to claim 1, wherein the at least one electrically operable light source mounted on the substrate comprises a plurality of electrically operable light sources on the first major surface of the substrate, each electrically operable light source being in electrical communication with at least one of the electrically conductive pathways on the first major surface of the substrate.

7. An assembly for making a glazing comprising: an electrical device comprising a substrate having a first major surface and a second opposing major surface, wherein directly on the first major surface of the substrate are at least two electrically conductive pathways in electrical communication with at least one electrically operable light source on the substrate, the at least one electrically operable light source on the substrate being a first electrically operable light source on the substrate, and on at least a portion of the second major surface of the substrate is an infrared radiation reflecting film for reducing the amount of infrared radiation that passes from the second major surface of the substrate to the first major surface of the substrate, wherein the at least two electrically conductive pathways include a first electrically conductive pathway and a second electrically conductive pathway arranged such that upon electrically connecting the first and second electrically conductive pathways to a power supply, the first electrically operable light source switches on; and at least one pane of glazing material and means for attaching the electrical device to the at least one pane of glazing material.

8. A glazing pane comprising: an electrical device comprising a substrate having a first major surface and a second opposing major surface, wherein directly on the first major surface of the substrate are at least two electrically conductive pathways in electrical communication with at least one electrically operable light source on the substrate, the at least one electrically operable light source on the substrate being a first electrically operable light source on the substrate, and on at least a portion of the second major surface of the substrate is an infrared radiation reflecting film for reducing the amount of infrared radiation that passes from the second major surface of the substrate to the first major surface of the substrate, wherein the at least two electrically conductive pathways include a first electrically conductive pathway and a second electrically conductive pathway arranged such that upon electrically connecting the first and second electrically conductive pathways to a power supply, the first electrically operable light source switches on; and a pane of glazing material, wherein the electrical device is attached to the pane of glazing material by at least one ply of adhesive interlayer material.

9. A method of making a laminated glazing comprising: (i) providing an unlaminated stack comprising, in the following sequence, a first pane of glazing material, a first ply of adhesive interlayer material, an electrical device, a second ply of adhesive interlayer material and a second pane of glazing material, wherein the electrical device comprises a substrate having a first major surface and a second opposing major surface, wherein directly on the first major surface of the substrate are at least two electrically conductive pathways in electrical communication with at least one electrically operable light source on the substrate, the at least one electrically operable light source on the substrate being a first electrically operable light source on the substrate, and on at least a portion of the second major surface of the substrate is an infrared radiation reflecting film for reducing the amount of infrared radiation that passes from the second major surface of the substrate to the first major surface of the substrate, wherein the at least two electrically conductive pathways include a first electrically conductive pathway and a second electrically conductive pathway arranged such that upon electrically connecting the first and second electrically conductive pathways to a power supply, the first electrically operable light source switches on, and (ii) laminating together the unlaminated stack to join the first pane of glazing material to the second pane of glazing material.

10. A laminated glazing comprising: a first pane of glazing material, a second pane of glazing material, a first ply of adhesive interlayer material, a second ply of adhesive interlayer material and an electrical device, wherein the first and second plies of adhesive interlayer material and the electrical device are between the first and second panes of glazing material; the electrical device is between the first and second plies of adhesive interlayer material and the electrical device comprises a substrate having a first major surface and a second opposing major surface; further wherein directly on the first major surface of the substrate are at least two electrically conductive pathways in electrical communication with at least one electrically operable light source mounted on the substrate, the at least one electrically operable light source mounted on the substrate being a first electrically operable light source mounted on the substrate; and on at least a portion of the second major surface of the substrate is an infrared radiation reflecting film for reducing the amount of infrared radiation that passes from the second major surface of the substrate to the first major surface of the substrate; and wherein the at least two electrically conductive pathways include a first electrically conductive pathway and a second electrically conductive pathway arranged such that upon electrically connecting the first and second electrically conductive pathways to a power supply, the first electrically operable light source switches on.

Description

(1) The invention will now be described with reference to the following figures (not to scale) in which,

(2) FIG. 1 shows a schematic cross-sectional view of a known laminated glazing incorporating a light emitting diode mounted on a circuit board;

(3) FIG. 2 shows a schematic exploded cross-sectional view of the laminated glazing shown in FIG. 1;

(4) FIG. 3 shows a schematic cross-sectional view of another known laminated glazing incorporating a light emitting diode mounted on a circuit board;

(5) FIG. 4 shows a schematic exploded cross-sectional view of the laminated glazing shown in FIG. 3;

(6) FIG. 5 shows a schematic cross-sectional view of a laminated glazing incorporating a light emitting diode mounted on a circuit board according to the present invention;

(7) FIG. 6 shows a schematic exploded cross-sectional view of the laminated glazing shown in FIG. 5;

(8) FIG. 7 shows a schematic isometric view of an electrical device in accordance with the present invention;

(9) FIG. 8 shows a schematic plan view of the electrical device shown in FIG. 7;

(10) FIG. 9 shows a schematic cross-sectional view of the electrical device shown in FIGS. 7 and 8;

(11) FIG. 10 shows a schematic isometric exploded view of a laminated glazing in accordance with the present invention;

(12) FIG. 11 shows a schematic cross-sectional view of the laminated glazing shown in FIG. 10;

(13) FIG. 12 shows a schematic exploded cross-sectional view of a glazing pane in accordance with the present invention; and

(14) FIG. 13 shows a schematic cross-sectional view of a double glazed unit pane in accordance with the present invention.

(15) With reference to FIGS. 1 and 2, there is shown a laminated glazing 1 comprising a first pane of glass 3 joined to a second pane of glass 5 by means of first and second plies of polyvinyl butyral (PVB) 9, 11. Between the first and second plies of PVB 9, 11 is an electrical device 13 comprising a substrate 15 having first and second opposing major surfaces 15a, 15b. The substrate 15 is an optically transparent sheet of polyethylene terephthalate (PET) having a thickness of 0.1 mm-0.2 mm.

(16) A light emitting diode 17 is mounted on the first major surface 15a of the substrate 15. As is known in the art, a light emitting diode is an electrically operable light source. The light emitting diode 17 has a first electrical input and a second electrical input such that upon bringing the first electrical input of the light emitting diode 17 into electrical communication with a first output terminal of a suitable electrical power supply, and bringing the second electrical input of the light emitting diode 17 into electrical communication with a second output terminal of the suitable power supply, electrical power is provided to the light emitting diode to switch the light emitting diode 17 “on” i.e. the light emitting diode goes from an unenergized state wherein no light is emitted by the light emitting diode to an energised state wherein light is emitted by the light emitting diode.

(17) Electrically conductive pathways (not shown) are on the first major surface 15a and are in electrical communication with the electrical inputs of the light emitting diode 17 for providing electrical power thereto. Suitably the electrically conductive pathways are an electrically conductive ink applied to the first major surface 15a by means of a printing process, such as screen printing or inkjet printing such that the electrically conductive pathways are in direct contact with the first major surface 15a of the substrate 15.

(18) The first pane of glass 3 has an optically transparent solar control coating 7 on a major surface thereof facing the first ply of PVB 9. The solar control coating 7 comprises an infrared radiation reflecting film of a type known in the art and may comprise at least one layer of silver. In the art, the pane of glass 3 with optically transparent solar control coating 7 on a major surface thereof are well known would be usually be referred to as a coated glass pane, or a coated glass sheet. The ply of PVB 9 is needed to bond the coated glass pane to the first major surface 15a of the substrate 15 because the solar control coating 7 and the substrate 15 are not adhesive. Likewise, the ply of PVB 11 is needed to bond the second glass pane 5 to the second major surface 15b of the substrate 15.

(19) With reference to FIGS. 3 and 4, there is shown a laminated glazing 21 comprising a first pane of glass 23 joined to a second pane of glass 25 by means of an interlayer structure comprising first, second and third plies of PVB 29, 31 and 33. Between the first and second plies of PVB 29, 31 is an electrical device 13 as described above having a light emitting diode 17 mounted on substrate 15.

(20) In between the second and third plies of PVB 31, 33 is an infrared radiation reflecting film 27 on a carrier ply 28 i.e. the infrared radiation reflecting film is a coating on the carrier ply 28. In FIGS. 3 and 4, the coated carrier ply is denoted by the numeral 30 i.e. the coated carrier ply 30 consists of the infrared radiation reflecting film 27 on a major surface of the carrier ply 28. Such a carrier ply provided with a coating comprising an infrared radiation reflecting film thereon is sold commercially by companies including Eastman (www.eastman.com) and 3M (www.3 m.com). Examples in the prior art are described in GB2080339B and WO2004/016416A2.

(21) In this example the carrier ply 28 is PET and the infrared radiation reflecting film 27 is a multilayer coating comprising at least one layer of silver.

(22) In order to incorporate the coated carrier ply 30 into the laminated glazing 21 it is necessary to position the coated carrier ply 30 between the second ply of the PVB 31 and the third ply of PVB 33 because the carrier ply 28 and the infrared radiation reflecting film 27 are not adhesive.

(23) Note that in FIGS. 3 and 4, the coated carrier ply 30 may be arranged such that the carrier ply 28 faces the second ply of PVB 31 and the infrared radiation reflecting film 27 faces the third ply of PVB 33.

(24) FIGS. 1-4 are illustrative of laminated glazings known in the art.

(25) FIGS. 5 and 6 show a laminated glazing 41 in accordance with the present invention.

(26) The laminated glazing 41 comprises first and second glass panes 43, 45 joined by an interlayer structure comprising first and second plies of PVB 49, 51. Between the first and second plies of PVB 49, 51 is an electrical device 50. The electrical device 50 comprises a substrate 46 having a first major surface 46a and an opposing second major surface (not labelled). A light emitting diode 47 (which is the same as light emitting diode 17 previously described) is mounted on the first major surface 46a of the substrate 46. The light emitting diode 47 has a first electrical input and a second electrical input such that upon bringing the first electrical input of the light emitting diode 47 into electrical communication with a first output terminal of a suitable electrical power supply, and bringing the second electrical input of the light emitting diode 47 into electrical communication with a second output terminal of the suitable power supply, electrical power is provided to the light emitting diode to switch the light emitting diode 47 “on” i.e. the light emitting diode goes from an unenergized state wherein no light is emitted by the light emitting diode, to an energised state wherein light is emitted by the light emitting diode.

(27) Electrically conductive pathways as previously described are also on the first major surface 46a in electrical communication with the light emitting diode 47. A first electrically conductive pathway is on and in direct contact with the first major surface 46a, the first electrically conductive pathway being in electrical communication with the first electrical input of the light emitting diode 47. A second electrically conductive pathway is also on and in direct contact with the first major surface 46a, the second electrically conductive pathway being in electrical communication with the second electrical input of the light emitting diode 47. Upon bringing the first electrically conductive pathway into electrical communication with a first output terminal of a suitable electrical power supply and bringing the second electrically conductive pathway into electrical communication with a second output terminal of the suitable power supply, electrical power is provided to the light emitting diode 47 to switch the light emitting diode 47 “on”.

(28) The substrate 46 is PET and has a thickness of 0.1 mm.

(29) On the second major surface of the substrate 46 and in direct contact therewith is an infrared radiation reflecting film 48. The infrared radiation reflecting film 48 is a multilayer coating comprising at least one layer of silver.

(30) The first ply of PVB 49 is in direct contact on one side with the first glass pane 43 and in direct contact on the other opposite side with the electrical device 50.

(31) The second ply of PVB 51 is in direct contact on one side with the second glass pane 45 and in direct contact on the other opposite side with the electrical device 50.

(32) As is apparent from FIGS. 5 and 6, the second ply of PVB 51 is in direct contact with the infrared radiation reflecting film that is on the PET substrate 46, the light emitting diode being on the opposite side of the PET substrate 46.

(33) It is preferred that in in the laminated glazing 41 all the individual components are arranged as a congruent stack, other than the electrical device because it is preferred that a portion of the electrical device extends beyond the periphery of the laminated glazing to allow electrical connection to be made to the electrically conductive pathways as will be described in more detail hereinafter. That is, it is preferred that the first glass pane 43 is coextensive with the first ply of PVB 49, that the second pane of glass 45 is coextensive with the second ply of PVB 51, that the first ply of PVB 49 is coextensive with the second ply of PVB 51 and that the electrical device 50 extends between the first and second plies of PVB 49, 51 to provide sufficient rejection of infrared radiation through the laminated glazing 41 whilst ensuring electrical power can still be provided to power the electrical device 50.

(34) FIG. 7 shows a schematic isometric representation of an electrical device 60 similar to the electrical device 50 described in relation to FIGS. 5 and 6, the main difference being that the electrical device 60 has three light emitting diodes, and not one, mounted on a substrate.

(35) The electrical device 60 comprises a substrate 62 having a first major surface 64 and an opposing second major surface (not labelled). The substrate 62 is a single sheet of PET which may suitably be cut from a larger sheet of PET as required. The substrate 62 would typically be referred to as monolithic.

(36) Mounted on the first major surface 64 of the substrate 62 are three light emitting diodes 65, 66 and 67. Each light emitting diode may emit light of the same colour i.e. the same wavelengths, or two or more may emit different colour light. At least one of the light emitting diodes 65, 66 and 67 may emit an infrared beam, for example at a wavelength of about 800 nm.

(37) Each light emitting diode 65, 66, 67 has a respective pair of electrical inputs (a first electrical input and a second electrical input) for providing electrical power to the respective light emitting diode as previously described.

(38) Also, on the first major surface 64 is a pair of electrical contacts, a first electrical contact 68 and a second electrical contact 69. The first electrical contact 68 and the second electrical contact 69 may be suitably screen printed using an electrically conductive ink.

(39) The first electrical contact 68 is in electrical communication with the first electrical input of each of the light emitting diodes 65, 66 and 67 via electrically conductive tracks 70a, 70b, 70c, 70d, 70e and 70f.

(40) The second electrical contact 69 is in electrical communication with the second electrical input of each of the light emitting diodes 65, 66 and 67 via electrically conductive tracks 71a, 71b, 71c, 71d, 71e and 71f.

(41) As is evident from FIGS. 7 and 8, the three light emitting diodes 65, 66, 67 are electrically connected in parallel with the pair of electrical contacts 68, 69.

(42) If desired, one or more of the light emitting diodes 65, 66, 67 may be electrically connected in series with the pair of electrical contacts 68, 69.

(43) The pair of electrical contacts 68, 69 are on an end portion 72 of the substrate 62. When the electrical device 60 is incorporated into a laminated glazing, for example of the type shown in FIG. 5, the end portion 72 is not located between the first and second plies of PVB 49, 51 or the first and second panes of glass 43, 45 so that a suitable power supply may be electrically connected to the pair of electrical contacts 68, 69 to provide electrical power to the light emitting diodes 65, 66, 67.

(44) On the second major surface of the substrate 62 is a coating 74 comprising an infrared radiation reflecting film. The coating is in direct contact with the second major surface of the substrate 62. In an alternative embodiment to that shown, there may be an intermediate coating on the second major surface of the substrate 62, and the coating 74 is disposed on the intermediate coating on the second major surface of the substrate 62. An intermediate coating on the second major surface of the substrate may be used to provide the second major surface of the substrate with other properties prior to the coating 74 being disposed thereon.

(45) The electrical device 60 may be made in different ways.

(46) It is preferable to use a substrate 62 that already has an infrared radiation reflecting film on a major surface thereof (i.e. in direct contact with a major surface of the substrate), and then to print onto the uncoated side of the substrate the electrically conductive pathways using a suitable electrically conductive ink such that the electrically conductive pathways are in direct contact with the previously uncoated side of the substrate. Each light emitting diode may then be mounted onto this surface and the electrical inputs thereof can be electrically connected to the electrically conductive pathways using an electrically conductive adhesive. As mentioned above, suitable carrier films provided with a coating comprising an infrared radiation reflecting film thereon are commercially available.

(47) In a first alternative, a sheet of PET with no coatings on either major surface thereof may be used to make the electrical device. The electrically conductive pathways may first be printed onto one major surface of the sheet of PET, followed by depositing the infrared reflecting film onto the opposite major surface of the sheet of PET. The electrical inputs of the light emitting diodes may then be electrically connected to the electrically conductive pathways and mounted onto the sheet of PET.

(48) In a second alternative, which has essentially the same steps as the first alternative, following the printing of the electrical conductive pathways on one major surface of the sheet of PET, the electrical inputs of the light emitting diodes are electrically connected to the electrically conductive pathways and mounted to the sheet of PET. Thereafter the infrared reflecting film is deposited onto the other major surface of the sheet of PET not having the electrically conductive pathways thereon.

(49) FIG. 8 is a plan view of the electrical device 60 i.e. when viewed in the direction of arrow 76 shown in FIG. 7.

(50) As shown in FIG. 8, the electrically conductive pathway 70a is in electrical communication at one end with the first electrical contact 68 and at the other end with electrically conductive node 70g.

(51) The electrically conductive pathway 70b is in electrical communication at one end with the first electrical input of the light emitting diode 65 and at the other end with electrically conductive node 70g.

(52) The electrically conductive pathway 70c is in electrical communication at one end with the electrically conductive node 70g and at the other end with electrically conductive node 70h.

(53) The electrically conductive pathway 70d is in electrical communication at one end with the first electrical input of the light emitting diode 66 and at the other end with electrically conductive node 70h.

(54) The electrically conductive pathway 70e is in electrical communication at one end with the electrically conductive node 70h and at the other end with electrically conductive node 70i.

(55) The electrically conductive pathway 70f is in electrical communication at one end with the first electrical input of the light emitting diode 67 and at the other end with electrically conductive node 70i.

(56) The electrically conductive pathway 71a is in electrical communication at one end with the second electrical contact 69 and at the other end with electrically conductive node 71g.

(57) The electrically conductive pathway 71b is in electrical communication at one end with the second electrical input of the light emitting diode 65 and at the other end with electrically conductive node 71g.

(58) The electrically conductive pathway 71c is in electrical communication at one end with the electrically conductive node 71g and at the other end with electrically conductive node 71h.

(59) The electrically conductive pathway 71d is in electrical communication at one end with the second electrical input of the light emitting diode 66 and at the other end with electrically conductive node 71h.

(60) The electrically conductive pathway 71e is in electrical communication at one end with the electrically conductive node 71h and at the other end with electrically conductive node 71i.

(61) The electrically conductive pathway 71f is in electrical communication at one end with the second electrical input of the light emitting diode 67 and at the other end with electrically conductive node 71i.

(62) The electrically conductive pathways 70a, 70b, 70c, 70d, 70e, 70f, 71a, 71b, 71c, 71d, 71e and 71f and the electrically conductive nodes 70g, 70h, 70i, 71g, 71h, 71i are all in direct contact with the first major surface 64 of the substrate 62. It is also preferred that the first electrical contact 68 and the second electrical contact 69 are in direct contact with the first major surface 64 of the substrate 62.

(63) The electrically conductive pathways 70a, 70b, 70c, 70d, 70e, 70f, 71a, 71b, 71c, 71d, 71e and 71f and the electrically conductive nodes 70g, 70h, 70i, 71g, 71h, 71i may all be printed in the same printing operation with the same electrically conductive ink.

(64) The first electrical contact 68 and the second electrical contact 69 may be suitably screen printed using the same electrically conductive ink as used to screen print the electrically conductive pathways and/or electrically conductive nodes. It is also preferred that the first electrical contact 68 and the second electrical contact 69 are printed in the same printing operation used to print the electrically conductive pathways and/or electrically conductive nodes.

(65) In an alternative to the embodiment shown in FIGS. 7 and 8, there are no electrically conductive nodes, but the electrically conductive tracks are still in electrical communication as described above.

(66) FIG. 9 is a schematic cross-sectional view of the electrical device 60 viewed along the line A-A′ of FIG. 8.

(67) The light emitting diode 65 is arranged to emit a beam of light in the direction of arrow 65′. The light emitting diode 66 is arranged to emit a beam of light in the direction of arrow 66′. The light emitting diode 67 is arranged to emit a beam of light in the direction of arrow 67′.

(68) Any or all of the light emitting diodes 65, 66, 67 may be arranged to emit a beam of light in the opposite direction. This is illustrated for light emitting diode 67 showing (in phantom) a beam of light in the direction of arrow 67″ i.e. passing through the thickness of the substrate 62 and the infrared reflecting film 74.

(69) Although only three light emitting diodes are shown in FIGS. 7-9, there may be more than three light emitting diodes or there may be only one or two light emitting diodes mounted on the first major surface 64 of the substrate 62.

(70) FIG. 10 shows a schematic exploded perspective view of another laminated glazing 81. FIG. 11 shows a schematic cross-sectional view of the laminated glazing 81 of FIG. 10 through the line B-B′.

(71) In this example the laminated glazing 81 comprises a first glass pane 83 joined to a second glass pane 85 by means on an interlayer structure 87. The interlayer structure 87 consists of three plies of adhesive interlayer material (i.e. PVB, EVA or combinations of plies thereof) 89, 91 and 93. The first ply of adhesive interlayer material 89 is coextensive with the first glass pane 83. The second ply of adhesive interlayer material 91 is coextensive with the second pane of glass 85. The third ply of adhesive interlayer material 93 is located between the first and second plies of interlayer material 89, 91 and has a cut-out region therein to accommodate the electrical device 60. The cut-out region is along one edge of the third ply of adhesive interlayer material and the other three edges thereof are aligned with the respective edges of the first and second plies of adhesive interlayer material.

(72) FIG. 10 is representation of the stack of unlaminated components that may be laminated together using conventional lamination processes, for example using suitably high temperature and pressure, to produce the final laminated glazing 81.

(73) In the final laminated glazing 81 as shown in FIG. 11, the electrical device 60 is between the first and second plies of adhesive interlayer material 89, 91 and is located in the cut-out region of the third ply of adhesive interlayer material 93. Such a construction makes lamination simpler as the extra third ply of adhesive interlayer material (compared to a two-ply adhesive interlayer structure) makes it easier to accommodate the thickness of the electrical device 60 in between the first and second plies of adhesive interlayer material.

(74) In the final laminated glazing 81 the first ply of adhesive interlayer material 89 is adjacent to and in direct contact with the first glass pane 83 and the second ply of adhesive interlayer material 91 is adjacent to and direct in contact with the second glass pane 85. The third ply of adhesive interlayer material 93 is in direct contact with both the first and second plies of adhesive interlayer material 89, 91.

(75) FIG. 11 is a schematic cross-sectional representation through the line B-B′ in FIG. 10 and illustrates how the portion 72 extends beyond the periphery of the laminated glazing 81 such that electrical power may be supplied to the electrical device 60 via the electrical contacts 68, 69.

(76) At least one of the first, second and third plies of adhesive interlayer material 89, 91, 93 may be PVB or EVA.

(77) FIG. 12 shows an exploded cross-sectional view of a glazing pane 101 comprising an electrical device 113 of the type described with reference to FIGS. 7-9, except in this example the electrical device has only one light emitting diode, and not three.

(78) The glazing pane 101 comprises a glass pane 103, a ply of adhesive interlayer material 105, such as PVB or EVA, and an electrical device 113.

(79) The electrical device 113 is fixed to the glass pane 103 by means of the ply of adhesive interlayer material 105.

(80) The electrical device 113 consists of a PET substrate 109 having on one side a light emitting diode 107 and associated electrically conductive pathways, and on the other side an infrared radiation reflecting film 111.

(81) In FIG. 12, the light emitting diode is arranged to be between the glass pane 103 and the substrate 109, but the electrical device 113 may be configured to face the opposite way such that the infrared radiation reflecting film 111 is between the ply of adhesive interlayer material 105 and the PET substrate 109.

(82) Although in FIG. 12 only one ply of adhesive interlayer material 105 is present in the glazing pane 101, there may be two or more plies of adhesive interlayer material, one ply of adhesive interlayer material adjacent to and in direct contact with the glass pane 103 and a second ply of adhesive interlayer material adjacent to and in direct contact with the electrical device 113.

(83) FIG. 13 shows a schematic cross-sectional view of a portion of a double glazing unit 110 comprising the glazing pane 101 of FIG. 12. As is known in the art, a double glazing unit is often referred to as an insulated glazing unit, or an IGU for short. IGUs are known with two or more glazing panes with an airspace between opposing panes.

(84) The double glazing unit 110 comprises the glazing pane 101 spaced apart from glazing pane 115 by a perimeter seal 117 to define an air space 119. A spacer bar 118 may also be provided adjacent to the peripheral seal 117 to help maintain the spacing of the glazing panes 101, 115.

(85) The glazing pane 115 may be glass and may be thermally toughened.

(86) Although in the previous figures the laminated glazings are shown as being flat (or planar), it is within the scope of the present invention to provide a laminated glazing that is curved in at least one direction. Preferably the radius of curvature in the at least one direction is between 500 mm and 20000 mm, more preferably between 1000 mm and 8000 mm.

(87) In the preceding examples where glass panes were described, a suitable glass composition for the glass panes is a soda-lime-silica glass composition. A typical soda-lime-silica glass composition is (by weight), SiO.sub.2 69-74%; Al.sub.2O.sub.3 0-3%; Na.sub.2O 10-16%; K.sub.2O 0-5%; MgO 0-6%; CaO 5-14%; SO.sub.3 0-2%; Fe.sub.2O.sub.3 0.005-2%. Such a glass may be manufactured using the float process.

(88) Other glass compositions may be used, for example borosilicate glass.

(89) Furthermore, any or all of the glass panes in the preceding examples may be replaced by panes of other types of glazing material, for example plastic material such as polycarbonate.

(90) In addition, although the above examples use light emitting diodes emitting light in the visible region of the electromagnetic spectrum (wavelengths in the range 380 nm to 780 nm), light emitting diodes which emit in other regions of the electromagnetic spectrum, for example, infrared or ultra violet, may be used.

(91) The present invention provides particular advantage when a glazing requiring both solar control and an illumination function is required. By incorporating an electrical device as hereinbefore described, a solar control function may be provided to a glazing and less heat may be incident upon the illumination device. Less plies of adhesive interlayer material are required compared to using conventional solar control films on carrier plies because the same substrate may be used to carry both the electrical device (or devices) on one side thereof and on the opposite side the infrared radiation reflecting film, thereby providing an advantage that thinner (and therefore less heavy) laminated glazings may be produced.