FR3055474A1 - AUTOMOTIVE VEHICLE BOX COMPONENT COMPRISING A TRANSPARENT GLASS SUPPORTING ANTENNA ELEMENTS SERIGRAPHIES - Google Patents

Abstract

Trunk flap (10) of a motor vehicle (V) comprising at least a hinge portion (21) integral with the trunk flap (10) which is adapted to cooperate in rotation with at least one hinge portion secured to the frame (40) , said shutter being equipped with a transparent window (5) supporting at least one first aerial (A1) antenna (FM1) screen-printed on the pane (5), adapted to receive a radio signal in a determined frequency band, characterized in that the flap (10) is made of a non-electrically conductive material and in that it comprises an electric reference plane (8) attached to the shutter (10) between an edge of the window (5) and an edge of the flap (10), a receiving module (R1) electrically connected on the one hand to the aerial (A1) of the antenna (FM1) and, on the other hand, to the reference plane (8) , and electrical connection means (81) to the part of the hinge (21) integral with the flap (10), able to couple electrically the reference plane (8) to the frame (40) of the vehicle (V).

Description

Holder (s): PEUGEOT CITROEN AUTOMOBILES SA Société anonyme.

Extension request (s)

Agent (s): PEUGEOT CITROEN AUTOMOBILES SA Public limited company.

FR 3 055 474 - A1 (04) AUTOMOTIVE VEHICLE TRUNK COMPONENT OF THE ANTENNA ELEMENTS.

©) Trunk flap (10) of a motor vehicle (V) comprising at least one hinge part (21) secured to the trunk flap (10) which is able to cooperate in rotation with at least one hinge part secured to the chassis ( 40), said flap being fitted with a transparent window (5) supporting at least one first aerial (A1) antenna (FM1) screen printed on the window (5), capable of receiving a radio signal in a determined frequency band , characterized in that the shutter (10) is made of a material which does not conduct electricity and in that it comprises an electrical reference plane (8) attached to the shutter (10) between an edge of the glass ( 5) and an edge of the flap (10), a reception module (R1) electrically connected on the one hand to the aerial (A1) of the antenna (FM1) and, on the other hand, to the reference plane ( 8), and electrical connection means (81) to the part of the hinge (21) integral with the flap (10), capable of being cut electrically link the reference plane (8) to the chassis (40) of the vehicle (V).

EQUIPPED WITH A SUPPORTING TRANSPARENT GLASS

MOTOR VEHICLE TRUNK SHUTTER EQUIPPED WITH A TRANSPARENT GLASS SUPPORTING ANTENNA ELEMENTS

PRINTS

The present invention relates generally to the trunk shutters of motor vehicles equipped with transparent panes and more particularly the flaps whose panes support antenna elements which are screen printed on the panes.

A window is designated indifferently by rear window and the boot lid by tailgate or more generally by rear window.

The antennas are increasingly integrated so that they are no longer visible from outside the vehicle, allowing the latter to present a more harmonious appearance, in keeping with current tastes of the public. The drawbacks linked to the use of protruding equipment, which relate to aerodynamics, noises, vibrations, sealing, vandalism are thus greatly reduced.

That said, it is important that the antenna is placed in an environment such that it can continue to perform its essential function which consists in transducing an electromagnetic field (external to the vehicle), in an electrical signal exploitable by radio, mounted in the vehicle, with satisfactory quality.

A compromise is therefore always to be sought between the position of the antenna which is desired to be as less visible as possible and its radiation performance which is all the more affected as the radiative structure of the antenna is integrated into the vehicle and in particular close to its metallic parts.

The current state of the art offers many possibilities for so-called hidden antennas, in particular for the following three radio reception functions:

FM Radio (Frequency Modulation between 76 MHz and 108 MHz), AM Radio (Amplitude Modulation) between 140 kHz and 1.7 MHz, DAB (Digital Audio Broadcast).

For a vehicle comprising a boot lid, the window is used as a support for the receiver element of the FM antennas, also designated by "aerial".

The term antenna includes the aerial, its reception module and the electrical and connector connections between the aerial and the module on the one hand, and the module and its power supply on the other.

In general, each of the FM, AM, DAB 10 hidden antenna functions implements an aerial and a reception module dedicated to the antenna, as close as possible to it.

FIG. 1 illustrates a boot flap 1 of the prior art, connected to the body 40 of a vehicle V by two articulation hinges 3 and 4 as visible by an observer placed at the rear of the vehicle V and looking towards the interior of vehicle V, boot lid 1 open.

The open trunk flap 1 reveals, on the one hand, the passenger compartment H of the vehicle V and, on the other hand, the upper part of the flap 1, located between the window 5 and the upper edge of the flap 1, voluntarily devoid of its trim elements to reveal the reception modules R1 and R2 of the antennas FM1 and FM2 as well as the harnesses and connectors FC for supplying the reception modules R1 and R2 and of the defrosting network 6 of the window 5.

The window 1 is a fixed transparent glass or plastic window supporting the aerials A1, A2 of the antennas FM1, FM2. On the same window 1, there is also provided the defrost network 6 of the window 1 of the conventional type where this couple the aerials A1, A2 of the antennas FM1, FM2.

The aerials A1 and A2 of the antennas FM1, FM2, as well as the deicing network 6 are deposited on the surface of the window 1 by a conventional screen printing process. The overhead lines A1 and A2 are connected at one of their ends to their respective reception module R1, R2 by a section of wired electrical connection L1, L2.

Figure 2 illustrates the circled area of Figure 1.

The aerial A1 of the antenna FM1 consists of at least one conductive track 5 in the upper part of the window 5, near the upper edge of the flap 1.

The reception module R1 typically comprises a circuit carrying out the impedance adaptation of the aerial A1 to the characteristic impedance of the coaxial cable leaving the module R1, that is to say equal to a value as close as possible to 50 or 75 ohms.

FM reception is improved by having several FM antennas, for example two, FM1 and FM2, respectively covering the same frequency bands.

The vehicle radio system V can have several FM tuners 15 each connected to a dedicated antenna (FM1, FM2, ...) and software for processing the radio signals received by the antennas. This processing makes it possible to simulate a directional antenna which would be systematically oriented in an optimal manner. One of the antennas can also be used for updating radio parameters such as the frequency list and RDS / ΤΑ monitoring (Radio Data System / Traffic Announcement) among others.

The aerials A1 and A2 of each antenna FM1, FM2 respectively comprise horizontal conductive tracks (parallel to the transverse direction of the vehicle) arranged symmetrically on either side of the median longitudinal vertical plane M.

These tracks start respectively from an opposite lateral edge of the window pane 1 and extend in opposite transverse directions.

The overhead lines A1 and A2 comprise a screen-printed track (or line) of a suitable length connected to the receiver module which is referenced to the mass of the vehicle (electrical mass formed by the chassis of the vehicle 40) via the metallic flap 1 and electrical conductor, its rotation being guaranteed by the hinges 3 and 4 also made of metal.

The shutter on which the window supporting the screen-printed antenna is implanted being metallic, it naturally offers an electrically conductive surface, which is generally called “ground plane” or implied reference plane of electrical potential reference, and which interacts with the aerial with regard to the reception characteristics of the antenna either by adapting its reception characteristics (antenna diagram) and / or reducing the electromagnetic disturbances (EMC: Electromagnetic Compatibility) due to the environment of the antenna .

Disturbances are generally measured at the base of the antenna. In the case of an antenna whose aerial is screen printed, the antenna base corresponds to the end of the aerial which is opposite the free end of the conductive track, and which is electrically connected to the reception module .

A problem then arises with the trunk flaps which are no longer metallic but produced from composite materials, electrically non-conductive. There is then no longer a "metallic" reference plane and the antenna is then more sensitive to electromagnetic interference, in particular to electromagnetic radiation from other electrical components present in the environment close to the antenna such as the electrical beams and computers. electronics installed in the shutter.

Composite materials are nowadays more and more used in the industry and, in particular in the automobile industry to realize certain bodywork parts such as, for example, trunk flaps.

These materials offer excellent mechanical properties, more freedom in the geometry of the parts and their lightness allows the reduction of CO2 emissions.

The composite materials used in the manufacture of body parts generally consist of a polymer matrix and a fiber-based reinforcing element.

These materials are considered plastic and the parts made from them do not conduct electricity. They can therefore no longer be used as a reference plane, such as a ground plane for an aerial aerial screen printed on the glass supported by the boot lid.

The present invention aims to provide a solution to this problem while improving the efficiency of the antenna.

Its first object is a motor vehicle trunk flap comprising at least one hinge part secured to the trunk flap which is able to cooperate in rotation with at least one hinge part secured to the chassis, said flap being fitted with a window pane. transparent supporting at least a first aerial antenna screen printed on the glass capable of receiving a radio signal in a determined frequency band.

The shutter according to the invention is characterized in that it is made of a material which does not conduct electricity and in that it comprises an electrical reference plane attached to the shutter between an edge of the glass and an edge of the flap, a reception module electrically connected on the one hand to the aerial of the antenna and, on the other hand, to the reference plane, and means of electrical connection to the part of the hinge integral with the flap, suitable for electrically couple the reference plane to the vehicle chassis.

According to one characteristic, the air is coupled to a screen-printed defrost network on the glass and disposed near an edge of the glass, and the reference plane is attached to the shutter between an edge of the shutter and the edge of the window near which the aerial is placed.

According to another characteristic, the reception module is arranged on the reference plane.

According to another characteristic, the glass supports at least one second aerial aerial screen printed on the glass, the first and second aerial being arranged on either side of the median plane of the flap passing through the edge with respect to which the first and second aerials extend in parallel.

According to another characteristic, the electrical connection means comprise at least one electrical connection tab connected mechanically or by bonding with the hinge part secured to the flap.

According to another characteristic, the flap comprises two hinge parts disposed respectively near the outer edges of the boot flap and the reference plane comprises two electrical connection tabs; each tab extending respectively opposite each of the hinge parts, integral with the boot lid.

According to another characteristic, the electrical connection means comprise a wire connection of determined length between the reference plane and the chassis of the vehicle in the case where the hinge part secured to the flap and the hinge part secured to the chassis in which the part integral with the shutter is capable of being engaged to ensure the rotation of the shutter around the chassis, are not electrically conductive.

The second object of the invention is a motor vehicle comprising a boot lid as described above.

Other characteristics and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the appended drawings, in which:

- Figure 1, already described, shows the rear part of a motor vehicle comprising an electrically conductive trunk flap, of the prior art, equipped with a window on which appear screen printed electrical circuit elements, Open chest ;

- Figure 2, already described, shows a detail of Figure 1 (circled area);

- Figure 3 shows the rear part of a motor vehicle comprising a non-electrically conductive trunk flap, according to the invention, equipped with a window on which appear screen printed electrical circuit elements, open trunk flap;

- Figure 4 illustrates the yields of a first FM1 antenna compared between reference plane in contact with the hinges of the shutter or not;

- Figure 5 illustrates the yields of a second FM2 antenna, compared between reference plane in contact with the hinges of the shutter or not;

- Figure 6 illustrates the result of the EMC disturbance measurements at the foot of FM1 antenna, compared between reference plane in contact with the hinges of the shutter or not; and

- Figure 7 illustrates the result of the EMC disturbance measurements at the foot of the FM2 antenna, compared between reference plane in contact with the hinges of the shutter or not.

In the figures, elements which are identical or fulfill the same function are designated by the same reference numerals.

FIG. 3 schematically represents the rear part of a motor vehicle V comprising a trunk flap 10 which is not electrically conductive, made from a non-electrically conductive composite material.

The trunk flap 10 is shown open and reveals on the one hand, the interior of the passenger compartment H of the vehicle V and, on the other hand, the defrost network 6 of the window 1 as well as two antennas FM1 and FM2 each comprising an aerial A1 respectively A2, a reception module R1 respectively R2 and the electrical connection links L1 and L2 between the aerial A1, A2 and the reception modules R1, R2.

The two antennas FM1 and FM2 formed by their aerials A1, A2, their reception modules R1, R2 and their electrical connection connections L1, L2 are arranged symmetrically on the window 5 on either side of the median plane M of the shutter 10 also corresponding to the median plane of the window 5.

The overhead lines A1 and A2 are arranged near the edge of the window 5 (upper edge), between the deicing network 6 and the edge (upper edge) of the window 5. The conductive tracks forming the overhead lines A1 and A2 extend parallel to this edge, from the median plane M of the shutter 1 (also corresponding to the median plane of the window 5) towards the lateral outer edges of the window 5, horizontally in opposite directions.

In known manner, the electromagnetic coupling between the conductive tracks forming the overhead lines A1 and A2 and the conductive tracks forming the deicing network 6, is determined to optimize the efficiency of the antennas FM1 and FM2.

The two antennas FM1 and FM2 are for example capable of receiving radio signals in a frequency band between

87.5 MHz and 108 MHz.

The shutter 10 made of non-conductive composite material also includes a reference plane on which the reception modules rest, which is made for example from an aluminum adhesive tape stuck on the shutter 10 or integrated in the shutter.

In the example described with reference to FIG. 3, the large dimension of the reference plane 8 extends parallel to the edge (upper edge) of the window 5 and its length is similar to the large dimension of the window 5 also general rectangular shape. Other dimensions and geometric shapes can be given in reference plane 8.

The plane 8 is shaped to present means of electrical connections 81 and 82 in the form of two legs, or tongues, electrically conductive, at each end of the plane 8 opposite the parts of hinges 21 and 22 belonging to the flap 10 which join in rotation, with the complementary parts of the hinge belonging to the chassis 40, the flap 10 on the chassis 40 of the vehicle V.

These tabs 81, 82 correspond to extensions of the reference plane 8 brought into contact with the parts of the hinges 21 and 22 integral with the flap 10, mechanically connected or by bonding with the latter. The better the electrical contact between these tabs 81, 82 and the parts of the hinges 21, 22 where the flap is fixed, the better the result. Just connecting a leg 81 or 82 to one of the hinges may be enough to guarantee the performance increase.

Insofar as the hinges are metallic, the reference plane 8 of the FM antennas behaves like a reference plane of electrical potential in the FM band, connected to the chassis 40.

The receiving modules R1 and R2 must be referenced to the reference plane 8. The electrical connection between the module R1, R2 and the reference plane 8 can be made either by a wired connection, or by a strip of conductive tape and fixed lug on plane 8 without exceeding 20 cm, either directly by contact with one of the faces of the reception module R1, R2, the mass of the electronic circuit contained in the module is connected to it.

The fact of connecting this reference plane 8 to the metal hinges ensuring the operation of the flap relative to the chassis 40 of the vehicle V, increases the efficiency of the antennas FM1, FM2 by a gain of almost 3 dB while reducing the level of electromagnetic disturbance at the foot of the FM1, FM2 antennas.

Overall, a marked increase in the level of radio service in traffic is observed in the FM band.

FIGS. 4 and 5 respectively illustrate the improvement in the efficiency of the antennas FM1 and FM2, expressed in dB, depending on whether the reference plane 8 is connected or not to the hinges 21, 22 for the FM band.

Figures 6 and 7 respectively illustrate the reduction of the 5 electromagnetic disturbances at the feet of the FM1 and FM2 antennas, expressed in dBpV, depending on whether the reference plane 8 is connected or not to the hinges 21,22 for the extended FM frequency band 76- 108 MHz.

In the configuration described, the reference plane 8 of the antennas FM1, FM2 is in "low impedance" contact (close to 0 Ohm) with the chassis 40 of the vehicle V with regard to the electrical signals in the FM band. The impedance of the hinges 21,22 beyond a few tens of MHz being lower than the impedance of a wired link of more than 1 m (length of the link generally used to bring the chassis 40 into contact with the reference plane 8).

In the case where devices carrying direct currents, such as the defrosting network 6 of the window, are connected to the reference plane 8, a wire connection 9 between the chassis 40 of the vehicle V and the reference plane 8 remains necessary in the case where the two parts of the hinges ensuring the movement of the shutter are not electrically conductive.

The present invention is not limited to the number of antennas and their shape (in general one or two FM antennas are present on the glazing).

The impact is independent of the shape of the reference plane.

The ground plane contact is made at the part of the hinge attached to the boot lid.

The principle works with hinges 21, 22, the two parts of which are electrically conductive or non-conductive.

Any type of conductive material can be used for the reference plane 8; this plane 8 being placed on the upper part of the shutter 10 while being glued or integrated into the shutter 10.

The effect can be transposed to other radio reception bands 5 using the same screen aerial antenna concept.

Claims (8)

1. Trunk flap (1; 10) of a motor vehicle (V) comprising at least one hinge part (21) secured to the trunk flap (10) which is able to cooperate in rotation with at least one hinge part secured to the chassis (40), said flap being equipped with a transparent window (5) supporting at least a first aerial (A1) antenna (FM1) screen printed on the window (5), capable of receiving a radio signal in a band of determined frequencies, characterized in that the shutter (10) is made of a material which does not conduct electricity and in that it comprises an electrical reference plane (8) attached to the shutter (10) between an edge of the window (5) and an edge of the flap (10), a reception module (R1) electrically connected on the one hand to the aerial (A1) of the antenna (FM1) and, on the other hand, to the plane of reference (8), and electrical connection means (81) to the part of the hinge (21) integral with the flap ( 10), capable of electrically coupling the reference plane (8) to the chassis (40) of the vehicle (V). 2. Trunk flap (10) according to claim 1, characterized in that the air (A1) is coupled to a deicing network (6) screen printed on the glass (5) and disposed near an edge of the window (5), and in that the reference plane (8) is attached to the shutter (10) between an edge of the shutter and the edge of the window (5) near which the aerial (A1) is disposed. 3. Trunk flap (10) according to one of the preceding claims, characterized in that the reception module (R1) is arranged on the reference plane (8). 4. Trunk flap (10) according to one of the preceding claims, characterized in that the window (5) supports at least one second aerial (A2) antenna (FM2) screen printed on the window (5), the first and second aerials (A1, A2) being arranged on either side of the median plane (M) of the flap (10) passing through the edge with respect to which the first and second aerials (A1, A2) extend parallel. 5. Trunk flap (10) according to any one of the preceding claims, characterized in that the electrical connection means (81) comprise at least one electrical connection tab connected mechanically or by bonding with the hinge part (21 ) in solidarity with 5 flap (10). 6. Trunk flap (10) according to the preceding claim, characterized in that it comprises two hinge parts (21,22) respectively disposed near the outer edges of the trunk flap (10) and in that the plane of reference (8) has two connection lugs 10 electric (81, 82), each tab (81, 82) extending respectively opposite each (21, 22) of the hinge parts, integral with the boot lid (10). 7. Trunk flap (10) according to one of the preceding claims, characterized in that the electrical connection means comprise 15 a wire connection (9) of determined length between the reference plane (8) and the chassis (40) of the vehicle (V) in the case where the hinge part (21) integral with the flap (10) and the part of hinge secured to the chassis (40) in which the part (21) secured to the flap (10) is capable of being engaged to ensure the rotation of the flap (10) around the chassis (40), are not 20 electrically conductive. 8. Motor vehicle (V) comprising a boot lid (10) according to any one of claims 1 to 7.