GB2638691A

GB2638691A - A vehicle window

Info

Publication number: GB2638691A
Application number: GB2402760.9A
Authority: GB
Inventors: Chirea Silviu; Latham Colin
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2024-02-27
Filing date: 2024-02-27
Publication date: 2025-09-03
Also published as: GB202402760D0

Abstract

A vehicle window 10 comprises an electrical circuit 20 for heating the window. The electrical circuit comprises a pattern of wires 22 which has a first region 24 and a second region 25. The wires 26 forming the first region have a resistance per unit length greater than that of the wires 27 forming the second region, and the area of the window occupied by the first region is less than the area of the window occupied by the second region. The first region may be trapezoidal in shape and located in a central portion of the window, such that the area occupied by the first region decreases in height from the centre of the first region towards the edges thereof. A vehicle backlight and a vehicle are also described.

Description

A VEHICLE WINDOW

TECHNICAL FIELD

The present disclosure relates to a vehicle window. Aspects of the invention relate to a vehicle window, a vehicle backlight and a vehicle.

BACKGROUND

It is known to provide vehicle windows with heaters in the form of electrical circuits comprising a plurality of spaced wires. Such heaters are useful for heating the window to melt frost and ice which may impair a vehicle user's field of view. Heaters comprising electrical circuits are commonly used to heat front windscreens and rear backlights of vehicles.

Vehicle users must either pre-condition their vehicles ready for use in cold or frosty conditions by operating the window heater before the anticipated departure time, or operate the heater upon entering the vehicle and wait until the heater has defrosted the window sufficiently before departing.

It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a window, a backlight and a vehicle as claimed in the appended claims.

According to an aspect of the present invention there is provided a vehicle window, the window comprising an electrical circuit for heating the window, wherein the electrical circuit comprises a pattern of wires having a first region and a second region, wherein the wires forming the first region of the pattern have a resistance per unit length greater than that the wires forming the second region of the pattern. Optionally the area of the window occupied by the first region of the pattern is less than the area of the window occupied by the second region of the pattern.

The present invention is advantageous as the higher heat production of the greater resistance wires in the first region of the pattem provides the ability to preferentially defrost a particular area of the window. Where that area is relatively small compared to the overall size of the window, a targeted area of the window may advantageously be defrosted.

Optionally the first region of the pattern is located in a central portion of the window. This is beneficial as preferential defrosting of the central portion of the window allows a vehicle user to rapidly achieve a safe field of view. This may be achieved by the first region of the pattern being surrounded by the second region of the pattern. Alternatively, the second region of the pattern may comprise a first sub-region and a second subregion, wherein the first region of the pattern is located between the first and second sub-regions of the second region of the pattern.

In one example, the area occupied by the first region of the pattern may decrease in height from the centre of the first region of the pattern towards the edges of the first region of the pattern. This is advantageous as this shape provides both a wide and high field of view.

Optionally the wires forming the first region of the pattern have a first thickness and the wires forming the second region of the pattern have a second thickness providing the ability to change the resistance of the wires by varying their thickness.

The wires forming the first region of the pattern are optionally thinner than the wires forming the second region of the pattern to provide greater resistance per unit length in the first region of the pattern. Thinner wires allow for closer spacing of the wires without impairing visibility.

The wires forming the first region of the pattern may comprise a different material composition to the wires forming the second region of the pattern providing the ability to change the resistance of the wires by varying their material composition.

In one example, the wires forming the first region of the pattern may have a different cross-sectional area to the wires forming the second region of the pattern providing the ability to change the resistance of the wires by varying their cross-section.

Optionally the average distance between the wires forming the first region of the pattern is less than the average distance between the wires forming the second region of the pattern. This is advantageous as closer spacing of wires provides a greater density of heating elements.

At least some of the wires forming the first region of the pattern may optionally comprise a plurality of electrically parallel wires which extend between a first portion of wire forming a first electrical path in the second region of the pattern and a second portion of wire forming the first electrical path in the second region of the pattern. This provides an efficient method of incorporating the first region of the pattern with the second region of the pattern.

The plurality of electrically parallel wires may comprise three electrically parallel wires to provide an even distribution of heat without undue complexity.

In one example, the backlight may comprise a window as described above, and the shape of the first region of the pattern of wires may conform to the shape of the intersection between the backlight and a predetermined rear view mirror field of view requirement in a predetermined vehicle design specification. This is advantageous as the backlight may be preferentially defrosted to provide a legal minimum area of visibility.

According to another aspect of the present invention there is provided a vehicle comprising the window or the backlight described above.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic representation of a vehicle backlight; and Figure 2 shows a vehicle in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

A vehicle 300 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 2. As shown in Figure 2, a backlight 10 is installed in a vehicle 300.

Figure 1 shows a schematic view of a vehicle backlight 10. The backlight 10 comprises and electrical circuit 20 for heating the backlight 10. The electrical circuit 20 comprises a pattern of wires 22 which has a first region 24 and a second region 25. The first region 24 of the pattern comprises wires 26 which have a resistance per unit length which is greater than that the wires 27 which form the second region 25 of the pattern.

The first region 24 of the pattern is broadly trapezoidal in shape and located in a central portion of the backlight 10 such that the area occupied by the first region 24 of the pattern decreases in height from the centre of the first region 24 of the pattern towards the edges of the first region 24 of the pattern. It will be understood that this configuration is not essential and that the first region 24 of the pattern of wires 22 may be of any suitable shape.

In the example shown in Figure 1, the first region 24 of the pattern of wires 22 is located between an upper (with respect to Figure 1) first sub-region 28 and a lower second sub-region 29 of the second region 25 of the pattern. Therefore, in the example of Figure 1, the second region 25 of the pattern is not continuous. In an alternative example (not shown), the first region of the pattern 24 may be surrounded by the second region 25 of the pattern.

The wires 26 which form the first region 24 of the pattern have a different thickness to the wires 27 which form the second region 25 of the pattern. In the example of Figure 1, the wires 26, 27 forming the first 24 and second 25 regions of the pattern of wires 22 respectively comprise the same material. The wires 26 forming the first region 24 of the pattern are thinner than the wires 27 forming the second region 25 of the pattern with the result that the resistance per unit length of the wires 26 forming the first region 24 of the pattern is greater than the resistance per unit length of the wires 27 which form the second region 25 of the pattern.

In alternative examples, the material composition of the wires 26, 27 forming the first 24 and second 25 regions of the pattern of wires 22 respectively may differ such that the relative thickness of the wires 26, 27 in each region of the pattern of wires 22 may differ from the example shown in Figure 1. If the resistivity of the wires 26, 27 forming the first 24 and second 25 regions of the pattern of wires 22 differ, the wires 26 forming the first region 24 of the pattern may have the same thickness as the wires 27 which form the second region 25 of the pattern, may have a greater thickness than the wires 27 which form the second region 25 of the pattern, or may have a lesser thickness than the wires 27 which form the second region 25 of the pattern, provided in each case that the resistance per unit length of the wires 24 forming the first region of the pattern is greater than that the resistance per unit length of the wires 27 which form the second region 25 of the pattern. Similarly, the wires 26, 27 forming the first 24 and second 25 regions of the pattern of wires 22 respectively may have different cross-sectional shapes. Nonetheless, as long as the resistance per unit length of the wires 24 forming the first region of the pattern is greater than that the resistance per unit length of the wires 27 which form the second region 25 of the pattern any suitable combination of wire material, size and/or shape may be used.

In the example shown in Figure 1, the average distance between the wires 26 forming the first region 24 of the pattern is less than the average distance between the wires 27 forming the second region 25 of the pattern. In addition, the wires 26 forming the first region 24 of the pattern comprise a plurality of groups 30 of electrically parallel wires which extend between a first portion 32 of wire forming a first electrical path 31 in the second region 25 of the pattern and a second portion 34 of wire forming the first electrical path 31 in the second region 25 of the pattern. For clarity only one electrical path 31 and one group 30 of parallel wires are labelled in Figure 1. It will be understood that each wire 27 in the second region 25 of the pattern of wires 22 that is split by a group 30 of wires 26 in the first region 24 of the pattern of wires 22 is similarly arranged. In some cases a wire 27 in the second region 25 of the pattern of wires 22 may be split by more than one group 30 of wires from the first region 24 of the pattern of wires. Such a wire is labelled by reference numeral 36 as an example.

The group 30 of electrically parallel wires comprise three electrically parallel wires in the example of Figure 1.

However, it will be understood that any number of electrically parallel wires may be used in any group 30 as desired. In another example, as shown by wires 38, 39 in Figure 1, a wire from the first region 24 of the of the pattern of wires may be arranged electrically in parallel with at wire from the second region 25 of the pattern of wires 22.

It is often desirable to defrost a particular portion of a backlight more rapidly that the remainder of the backlight.

For example, some authorities set a rear view mirror field of view requirement requiring that a particular height and width at a set distance behind the rear of the vehicle be visible. If a portion of the backlight corresponding to the shape of the intersection between the backlight and the predetermined rear view mirror field of view requirement is defrosted more rapidly than the remainder of the backlight, the vehicle will become ready for safe operation more rapidly. Because the wires 26 in the first region 24 of the pattern of wires 22 have a greater resistance per unit length than the wires 27 in the second region 25 of the pattern of wires, the backlight in the portion of the backlight 10 occupied by the first region 24 of the pattern of wires 22 will defrost more rapidly than the portion of the backlight 10 occupied by the second region 25 of the pattern of wires 22 if a suitable distribution of wires 22, such as that shown in Figure 1, is utilised. It will be understood that other arrangements of wires 22 in first and second regions 24, 25 may be used to the same effect. The particular shape of the portion of the backlight 10 corresponding to the shape of the intersection between the backlight and the predetermined rear view mirror field of view requirement will differ depending on the particular, predetermined, vehicle design specification.

It is typically the case that portion of the backlight 10 corresponding to the shape of the intersection between the backlight 10 and the predetermined rear view mirror field of view requirement has a surface area which is less than the remainder of the backlight 10. Therefore, the area of the backlight 10 occupied by the first region 24 of the pattern of wires 22 is less than the area of the backlight 10 occupied by the second region 25 of the pattern of wires 22. The backlight 10 may be configured so that the area of the backlight 10 occupied by the first region 24 of the pattern of wires 22 is less than the area of the backlight 10 occupied by the second region 25 of the pattern of wires 22 regardless of whether the smaller area occupied by the first region 24 of the pattern of wires 22 is deliberately designed to conform to the shape of the intersection between the backlight 10 and a predetermined rear view mirror field of view requirement.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application. In particular, the present invention has been described in the context of a backlight 10 of a vehicle 300. It will be appreciated that the invention may be used with any vehicle window. A backlight 10 of a vehicle 300 may be referred to as a rear windscreen, or tailgate glass.

Claims

CLAIMS1. A vehicle window, the window comprising an electrical circuit for heating the window, wherein the electrical circuit comprises a pattern of wires having a first region and a second region, wherein the wires forming the first region of the pattern have a resistance per unit length greater than that the wires forming the second region of the pattern, and wherein the area of the window occupied by the first region of the pattern is less than the area of the window occupied by the second region of the pattern.
2. The vehicle window according to claim 1, wherein the first region of the pattern is located in a central portion of the window.
3. The vehicle window according to any preceding claim, wherein the first region of the pattern is surrounded by the second region of the pattern.
4. The vehicle window according to claim 1 or 2, wherein the second region of the pattern comprises a first sub-region and a second sub-region, wherein the first region of the pattern is located between the first and second sub-regions of the second region of the pattern.
5. The vehicle window according to any preceding claim, wherein the area occupied by the first region of the pattern decreases in height from the centre of the first region of the pattern towards the edges of the first region of the pattern.
6. The vehicle window according to any preceding claim, wherein the wires forming the first region of the pattern have a first thickness and the wires forming the second region of the pattern have a second thickness.
7. The vehicle window according to claim 6, wherein the wires forming the first region of the pattern are thinner than the wires forming the second region of the pattern.
8. The vehicle window according to any preceding claim, wherein the wires forming the first region of the pattern comprise a different material composition to the wires forming the second region of the pattern.
9. The vehicle window according to any preceding claim, wherein wires forming the first region of the pattern have a different cross-sectional area to the wires forming the second region of the pattern.
10. The vehicle window according to any preceding claim, wherein the average distance between the wires forming the first region of the pattern is less than the average distance between the wires forming the second region of the pattern.
11. The vehicle window according to any preceding claim, wherein at least some of the wires forming the first region of the pattern comprise a plurality of electrically parallel wires which extend between a first portion of wire forming a first electrical path in the second region of the pattern and a second portion of wire forming the first electrical path in the second region of the pattern.
12. The vehicle window according to claim 11, wherein the plurality of electrically parallel wires comprise three electrically parallel wires.
13. A vehicle backlight, wherein the backlight comprises a window according to any preceding claim, and wherein the shape of the first region of the pattern of wires conforms to the shape of the intersection between the backlight and a predetermined rear view mirror field of view requirement in a predeterminedvehicle design specification.
14. A vehicle comprising the window according to any one of claims 1 to 12, or the backlight of claim 13.