GB2154403A - Heatable glazing panels - Google Patents

Heatable glazing panels Download PDF

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Publication number
GB2154403A
GB2154403A GB08402530A GB8402530A GB2154403A GB 2154403 A GB2154403 A GB 2154403A GB 08402530 A GB08402530 A GB 08402530A GB 8402530 A GB8402530 A GB 8402530A GB 2154403 A GB2154403 A GB 2154403A
Authority
GB
United Kingdom
Prior art keywords
strip
zone
bus
portions
panel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08402530A
Other versions
GB8402530D0 (en
Inventor
Jean-Marie Bertieaux
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AGC Glass Europe SA
Original Assignee
Glaverbel Belgium SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Glaverbel Belgium SA filed Critical Glaverbel Belgium SA
Priority to GB08402530A priority Critical patent/GB2154403A/en
Publication of GB8402530D0 publication Critical patent/GB8402530D0/en
Publication of GB2154403A publication Critical patent/GB2154403A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00Ohmic-resistance heating
    • H05B3/84Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/016Heaters using particular connecting means

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  • Resistance Heating (AREA)

Abstract

A glazing panel 1 for example for use as a heatable rear light for a motor vehicle, may bear electrical resistance heating means 2 arranged between conductive bus strips 3 deposited on the panel so that at least one said bus strip follows a curved or angled course, for example so that electrical connexions to the heating means 2 can be made at terminals 7 towards the centre of the top of the panel. In order to reduce the risk of local overheating of the bus strips 3 at the inner portions of the curved or angled zones 6, there is formed in such zone at least one elongate gap 8 which follows the course of the strip at that zone 6 to divide the strip 3 into a plurality of conductive portions. <IMAGE>

Description

SPECIFICATION Heatable glazing panels This invention relates to a glazing panel bearing electrical resistance heating means arranged between conductive bus strips deposited on the panel so that at least one said bus strip follows a curved or angled course.
A particularfield of use for such panels is as heatable rear lights for vehicles, especially motor cars.
Recent design trends in the motorvehicle industry have led to the increased production of vehicles having a reardoor hinged atthetop. As a resultofthis, vehicle manufacturers demand that electrical connexions to a rear light should be made at ortowardsthe centre of the top ofthe rear door so thatthe connecting wires are not subjectto any substantial risk of snagging. However it is also a usual requirement that bus strips feeding the heating element or elements should run upthesidemarginsofthe rearlight.
Accordingly, the bus strips are curved or angled at the top corners of the rear light so thatthey can lead to more or less centrally positionedterminalsforconne- xion of the wires required to feed currentto the heater.
Because the bus strips are relatively sharply curved or angled at the corners ofthe rear light, and because the currentfed to them tends to follow the shortest path, the inner portions ofthe bus strip are apt to become overheated there.
One suggestion which has been made in orderto overcome this problem isto deposit the bus strips with a non-uniform thicknesssothatthey have greater conductivityatthe regions where they are aptto overheat than they do elsewhere. This works very well, but it is an unsatisfactory solution to the problem because it gives rise to difficulties in deposition ofthe bus strips.
It is an object ofthe present invention to provide a glazing panel in which the disadvantage referred to above is alleviated in a manner which is simple to put into effect.
According to the present invention, there is provided a glazing panel bearing electrical resistance heating means arranged between conductive bus strips deposited on the panel so that at least one said bus strip follows a curved or angled course, characterised in that overthe or at least one zone where such bus strip is curved or angled, there is formed in such a strip at least one elongate gap which follows the course of the strip atthat zoneto divide the strip into a plurality of conductive portions.
By virtue of such a construction,the currentfeeding the heating means is caused to flow along each ofthe conductive portions atthe zone of sharp curvature or angle, so thatthe tendencyfor local overheating ofthe bus strip is reduced. It is much easier to form the bus strip in this way, since no steps need to be taken to ensure that it is deposited to a non-uniform thickness.
The strip may simply be applied bya serigraphic process in which no conductive material is applied to the gap area(s), or one or more gaps may be cut in the bus strips after deposition if preferred.
It is preferred that such bus strip includes substan tally straight length zones, and such gap zone extends from one substantially straight bus strip length zone to another. By the adoption ofthisfeature, it is possible to ensure that the current densities feeding to each bus strip portion are more nearly equal.
Advantageously,the widths and lengths of the conductive bus strip portions are so regulated that all such portions at any given zone have substantially the same electrical resistance. The adoption ofthis preferred feature helps to ensure that each such bus strip portion carries an equal current, further reducing the tendency for local overheating ofthe bus strip.
It has been found preferableforthereto be at least one such gap zone where there are at least four conductive bus strip portions.
A preferred embodiment of the present invention will now be described byway of example only, with reference to the accompanying diagrammatic drawings in which: Figure 1 is an elevational view of a glazing panel bearing electrical resistance heating means in accordance with this invention, and Figure 2 is a detail view of a cornerofthe panel of Figure 1.
In Figure 1, a sheet 1 of glazing material has deposited on oneface an array of heating elements 2 which extend between bus strips 3 also deposited on the glazing sheet 1. The bus strips 3 and the heating elements 2 are suitablyformed from a conductive enamel, and they may be applied in a single step using a serigraphictechnique well know perse.
In shape, the glazing sheet 1 approximates to an isoscelestrapezium with rounded corners, its upper and lower edges being parallel. Each bus strip 3 may notionally be divided into three zones, a substantially straight zone 4 leading up a side edge of the glazing sheet 1 and to which the heating elements 2 are directly attached, a second substantiallystraightzone 5 leading in along the top edge of the sheet 1 from a corner ofthe sheet 1 towards its centre, and a curved or angled zone 6 at that sheet corner.
Such a heatable glazing panel is primarily intended for use as a heatable rear lightfor a motorvehicle, especially of a motorvehicleofthetypehavinga rear door hinged atthe top. It will be appreciated that in practice the panel would be based on a non-planar sheet of glazing material andthat its entire periphery would usually be curved.
In ordertofacilitatetheconnexion of electrical leads (not shown) forsupplying power to the heating elements, aterminal 7 is provided closetothe central end of each straight bus strip zoneS atthe top edge of the glazing sheet 1. The terminals are located in that region so that, when the panel is used as a vehicle light in a top-hinged rear door, the connecting leads may be led directly to the main body ofthe vehicle between the rear door hinges. This reduces to a minimum any risk of those leads being snagged when the rear compartment of the vehicle is being loaded or unloaded.
Because the bus strips 3 are relatively sharply curved or angled in their zones 6 at the corners of the panel, and because anycurrentfedto them would tend to followthe shortest path, the radially inner portions ofthe bus strip would be apt to become overheated there, and in order to alleviate this disadvantage, at least one elongate gap 8 is provided which followsthe course of the strip atthatzoneto divide the strip into a pluralityofconductive portions.
This is shown more clearly in Figure 2.
In Figure 2, the curved bus strip zone 6 is bounded by lines 0-land 0-ll, where 0 isthecentre of curvature ofthe zone 6. It will be noted thatthere are three elongate gaps 8 which divide the bus strip 3 into four conductive portions respectively 9, 10, 11 and 12 within the zone 6, and also that those gaps extend to the lines 0-I and 0-ll, that is to say, from one substantially straight zone 4 ofthe bus strip 3 to the other such zone 5.
Sincetheterminal 7 (Figure 1 ) is somewhat remote along the bus strip zone 5, the line 0-ll may be considered as a line of equal potential across the bus strip 3. In orderthatthe line 0-I should also be a line of equal potential, it will be apparentthatthe resistances of the conductive portions 9 to 12 should be equal.
Assuming that the resistivity of the material of which the bus strip is made, expressed in Ohms per square, is constant over the area of the conductive portions, this condition is satisfied when the ratio (R - r)l(R + r) is constantforthe various portions, where R is a measure of the outer radius and r a measure ofthe inner radius ofthe respective portion. In other words, the ratios ofthe mean widths ofthe conductive portions to their mean lengths should be constant to satisfy that condition. Itwill be noted in Figu re 2 that each ofthe radially inner conductive portions 9, 10 and 11 has a lesserwidth than its radially outward neighbour, respectively 10, 11 and 12.
When the resistances of the conductive portions 9 to 12 are equal, itwill beapparentthatequal amounts of heat will be dissipated by Joule effect in each of the conductive bus strip portions 9 to 12 in the curved zone 6, so that the problem of local overheating there is avoided.
It will be appreciatedthatthe gaps 8should be narrowfor maximum conductivity over the curved zone 6.

Claims (4)

1. Aglazing panel bearing electrical resistance heating means arranged between conductive bus strips deposited on the panel so that at least one said bus strip follows a curved or angled course, characterised in that over the or at least one zone where such bus strip is curved or angled, there is formed in such strip at least one elongate gap which follows the course ofthe strip at that zone to divide the strip into a plurality of conductive portions.
2. A panel according to claim 1, wherein such bus strip includes substantially straight length zones, and such gap zone extends from one substantially straight bus strip length zone to another.
3. A panel according to claim 1 or 2, wherein the widths and lengths of the conductive bus strip portions are so regulated that all such portions at any given zone have substantially the same electrical resistance.
4. A panel according to any preceding claim, wherein there ;s at least one such gap zone where there are at least four conductive bus strip portions.
GB08402530A 1984-01-31 1984-01-31 Heatable glazing panels Withdrawn GB2154403A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08402530A GB2154403A (en) 1984-01-31 1984-01-31 Heatable glazing panels

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08402530A GB2154403A (en) 1984-01-31 1984-01-31 Heatable glazing panels

Publications (2)

Publication Number Publication Date
GB8402530D0 GB8402530D0 (en) 1984-03-07
GB2154403A true GB2154403A (en) 1985-09-04

Family

ID=10555822

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08402530A Withdrawn GB2154403A (en) 1984-01-31 1984-01-31 Heatable glazing panels

Country Status (1)

Country Link
GB (1) GB2154403A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0719075A3 (en) * 1994-12-22 1997-01-29 Pilkington Glass Ltd Electrically heated window
GB2327028A (en) * 1997-06-12 1999-01-06 Samsung Electronics Co Ltd Thin film type heater and method of manufacturing the same
EP0941016A2 (en) * 1998-03-02 1999-09-08 Josef Winter Curved electrode
DE102012219656A1 (en) * 2012-10-26 2014-04-30 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. SYSTEM FOR CARRYING OUT TOUCH-FREE MEASUREMENT ON A SAMPLE AND SAMPLE CARRIER

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1411265A (en) * 1971-09-30 1975-10-22 Saint Gobain Heatable non-conducting sheets
GB2091528A (en) * 1981-01-14 1982-07-28 Boussois Sa Heatable Panels
GB2091527A (en) * 1981-01-14 1982-07-28 Boussois Sa Heatable Panels
GB2091529A (en) * 1981-01-14 1982-07-28 Boussois Sa Heatable Panels

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1411265A (en) * 1971-09-30 1975-10-22 Saint Gobain Heatable non-conducting sheets
GB2091528A (en) * 1981-01-14 1982-07-28 Boussois Sa Heatable Panels
GB2091527A (en) * 1981-01-14 1982-07-28 Boussois Sa Heatable Panels
GB2091529A (en) * 1981-01-14 1982-07-28 Boussois Sa Heatable Panels

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0719075A3 (en) * 1994-12-22 1997-01-29 Pilkington Glass Ltd Electrically heated window
US5861606A (en) * 1994-12-22 1999-01-19 Pilkington Glass Limited Electrically heated window having busbar with curved corner piece
US6185812B1 (en) 1994-12-22 2001-02-13 Pilkington Glass Limited Electrically heated window
GB2327028A (en) * 1997-06-12 1999-01-06 Samsung Electronics Co Ltd Thin film type heater and method of manufacturing the same
EP0941016A2 (en) * 1998-03-02 1999-09-08 Josef Winter Curved electrode
DE19808667A1 (en) * 1998-03-02 1999-09-16 Josef Winter Bent electrode
EP0941016A3 (en) * 1998-03-02 2000-06-21 Josef Winter Curved electrode
DE19808667C2 (en) * 1998-03-02 2001-08-30 Josef Winter Bent electrode
DE102012219656A1 (en) * 2012-10-26 2014-04-30 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. SYSTEM FOR CARRYING OUT TOUCH-FREE MEASUREMENT ON A SAMPLE AND SAMPLE CARRIER

Also Published As

Publication number Publication date
GB8402530D0 (en) 1984-03-07

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)