Title: For a motor vehicle, an outside element providing a capacitive sensor, and a piece of bodywork including such an outside element
Abstract: The invention relates to an outside element for a motor vehicle, the element being designed to be fitted to the vehicle, e.g. on its bodywork, and comprising an essentially non-conductive protective screen (3), the element being characterized in that behind said protective screen if further comprises an electrically insulating film having two faces, each of which is covered at least in part in an electrically conductive material. The invention also provides a piece of bodywork provided with such a conductive element.
Patent Number: 6,879,250 Issued on 04/12/2005 to Fayt, et al.
| Inventors:
|
Fayt; Arnold (Aromas, FR);
Hilmarcher; Olivier (Montreal la Cluse, FR);
Guyon; Sebastien (Montreal la Cluse, FR)
|
| Assignee:
|
Compagnie Plastic Omnium (Lyons, FR)
|
| Appl. No.:
|
115070 |
| Filed:
|
April 4, 2002 |
Foreign Application Priority Data
| Current U.S. Class: |
340/436; 340/435; 340/468; 340/434; 340/472.1; 340/480; 340/562; 150/154; 150/166; 280/29; 280/727; 280/762; 280/770; 362/510; 362/549 |
| Intern'l Class: |
B60Q 001//00 |
| Field of Search: |
340/436,435,434,468,472,480,562
150/154,166
362/510,549
200/61.43,61
280/29,727,762,770
|
References Cited [Referenced By]
U.S. Patent Documents
| 3716445 | Feb., 1973 | Lemelson | 428/166.
|
| 4488745 | Dec., 1984 | Stokes | 293/155.
|
| 4546840 | Oct., 1985 | Yukishige et al. | 200/61.
|
| 4951985 | Aug., 1990 | Pong et al. | 200/61.
|
| 5394292 | Feb., 1995 | Hayashida | 340/435.
|
| 5672405 | Sep., 1997 | Plank et al. | 428/133.
|
| 5801340 | Sep., 1998 | Peter.
| |
| Foreign Patent Documents |
| 0110631 | Nov., 1983 | EP.
| |
| 0 952 046 | Oct., 1999 | EP.
| |
| 2 348 505 | Oct., 2000 | GB.
| |
| WO 89/08352 | Sep., 1989 | WO.
| |
Primary Examiner: Hofsass; Jeffery
Assistant Examiner: Previl; Daniel
Attorney, Agent or Firm: Oliff & Berridge, PLC
Claims
What is claimed is:
1. An element for a motor vehicle for fitting onto an outside surface of
the vehicle the element comprising:
an essentially non-conductive capping for fitting onto a side door, a rear
door, or a bumper shield of the vehicle; and
an electrically insulating film situated behind said capping, and having
two faces, each of which is coated at least in part with an electrically
conductive material;
wherein the element forms a capacitor with any obstacles with which the
vehicle might come into contact to determine whether a distance between
the vehicle and the obstacles is increasing or decreasing.
2. An element according to claim 1, in which the capping is made of a
plastic material.
3. An element according to claim 2, in which the plastic material is
transparent or translucent.
4. An element according to claim 3, in which the plastic material is a
methacrylate, a polypropylene, or a polycarbonate.
5. An element according to claim 2, in which the plastic material is
opaque.
6. An element according to claim 5, in which the plastic material is
colored by being bulk-dyed, by non-electrostatic painting, or by
overmolding a film.
7. An element according to claim 1, in which the electrically insulating
film is made of a thermoplastic polyester.
8. An element according to claim 1, in which the electrically conductive
material forms an open-work pattern, at least on one face.
9. An element according to claim 1, in which the film is shaped by
thermoforming to have a particular geometrical configuration corresponding
to the capping.
10. An element according to claim 1, in which the film is fixed to capping.
11. An element according to claim 1, in which the film is fixed directly to
the vehicle, and in which the capping is likewise fixed directly to the
vehicle, over the film.
12. A piece of bodywork, in particular a door panel, a rear door panel, or
a bumper shield, including an outside element according to claim 1.
Description
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to an outside element for a motor vehicle,
the element providing a capacitive sensor, and the invention also provides
a piece of bodywork including such an outside element.
2. Description of Related Art
In the state of the art, devices are already known for providing driving
assistance on the basis of ultrasound radar.
Such devices provide good results but they are relatively expensive given
their great complexity. That is why they are to be found almost
exclusively on top-of-range vehicles only.
In addition, they are unsightly insofar as the radar transceiver must have
a clear field of view in order to be able to operate. Given that such
transceivers are generally housed in bumper shields, that requires the
bumpers to be pierced, which gives rise to a certain amount of difficulty
in organizing the appearance of the vehicle, and also to a certain amount
of fragility for the sensors.
Furthermore, ultrasound sensors are relatively heavy at present and they
provide a detection envelope that is not very uniform.
There is another artificial vision technique which makes it possible to
detect movements of obstacles that might exist in the vicinity of a
vehicle: detection by means of a capacitive sensor.
In that technique, an antenna is placed on the vehicle bumper so as to form
a capacitor with each object around it, and thus in particular with any
obstacles with which the vehicle might come into contact.
The distance between the antenna and each such object is one of the factors
which determines the capacitance of the capacitor formed in this way.
Consequently, by using electronic means to measure this capacitance it is
possible to calculate the distance between the antenna and the object, or
at least whether said distance is increasing or decreasing by measuring
variations in the capacitance of the capacitor.
However, the difficulty with that technique lies in how the antenna is to
be positioned on a piece of bodywork.
SUMMARY OF THE INVENTION
An object of the invention is to propose a novel way of installing a
capacitive proximity-sensing antenna that is simple and inexpensive to
make and to install on a vehicle, while making full use of its capacitive
sensor function.
To this end, the invention provides an outside element for a motor vehicle,
for fitting onto the vehicle, e.g. onto its bodywork, the element
comprising an essentially non-conductive protective screen and being
characterized in that behind said protective screen it further comprises
an electrically insulating film having two faces, each of which is coated
at least in part in an electrically conductive material.
In the meaning of the present invention, the term essentially
non-conductive protective screen is used to mean a screen which, firstly
is made of a material that is electrically non-conductive, and secondly
has not been subjected to treatment for giving it electrical conduction
properties.
An example of treatment that could impart properties of electrical
conductivity to an initially non-conductive screen is that of
electrostatically painting parts made of plastics material. Such parts,
which are initially non-conductive, are coated with a conductive primer
which ensures that electrically charged particles of paint sprayed onto
said parts adhere thereto.
Consequently, in order to be considered as being essentially
non-conductive, in the meaning of the invention, a colored protective
screen must have been painted using a non-electrostatic painting
technique, or be bulk-dyed, or be covered in an overmolded decorative film
that is likewise non-conductive.
In the invention, the film carrying a conductive material on both faces
constitutes a conductive antenna which, in association with an electronic
device for measuring capacitance, acts as a capacitive sensor. Associated
with the protective screen, this sensor forms an element which can be
fitted onto various locations of a vehicle.
In a particular embodiment of the invention, the protective screen is made
of plastics material.
This screen can constitute a protective capping strip for fitting onto a
side door, onto a rear door, or onto a bumper shield, so as to warn of
bumps against those portions of the vehicle.
For ornamental purposes, and depending on the style of the vehicle, the
plastics material can be selected to be transparent or translucent so as
to leave the film carrying the two layers of conductive material visible.
Under such circumstances, it is advantageous for at least the face of the
film that is visible from the outside to carry the electrically conductive
material in the form of an open-work pattern, preferably a regular
pattern, giving the film as seen through the transparent or translucent
screen a decorative function marking the style of the vehicle and possibly
emphasizing the presence of the capacitive sensor on the vehicle.
The particular open-work pattern that is selected can be determined by
technical requirements, given the desired efficiency for the antenna, and
by decorative requirements, in order to obtain a particular decorative
appearance.
In addition, the fact of the conductive material forming an open-work
pattern serves to save material, since such material is potentially quite
expensive, without that harming the efficiency of the sensor, since a
continuous layer of conductive layer would in any event be of no use for
the intended function.
The conductive material can be a conductive ink or any other conductive
material selected as a function of the conductivity properties required
for the intended application.
The conductive material can be deposited by silkscreen printing on at least
one of the faces of the film, and a varnish can be added to cover it and
to protect it.
In the invention, the transparent plastics material can be a methacrylate,
a polypropylene, or a polycarbonate.
In another embodiment of the invention, the plastics material is opaque.
It can then retain its initial color or it can be bulk-dyed, which is
generally compatible in terms of appearance with it being used as a
protective strip for the bumper shield.
In a particular embodiment of the invention, the electrically insulating
film is made of a thermoplastic polyester. By way of example, the
polyester can be that sold by General Electric Plastics under the
trademark VALOX FR-1.
Said film can be shaped by thermoforming to have a particular geometrical
configuration corresponding to the protective screen.
Depending on the location of the element on the vehicle, various ways of
fixing the film and the protective screen can be envisaged.
The film can thus be fixed to the protective screen or it can be fixed
directly to the vehicle, with the protective screen being fixed to the
vehicle over the film.
The film can be fixed on the protective screen by a suitable arrangement of
the screen that leaves a narrow gap between the inside wall and the
vehicle, with the film being sandwiched therein and remaining plane
because of its own stiffness.
The film can also be stuck or heat-sealed to the inside wall of the
protective screen.
Another possibility is to overmold the protective screen onto the film.
Other fastening means could also be envisaged, for example such as giving
particular shapes to the screen, such as tongues when the screen is
opaque.
The invention also provides a piece of bodywork including an element as
described above.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood on reading the following
description given purely by way of example and made with reference to the
accompanying drawings, in which:
FIG. 1 is a three-fourths rear view of a motor vehicle fitted with an
outside element of the invention;
FIG. 2 is a diagrammatic exploded view of an antenna incorporated in an
outside element of the invention;
FIG. 3 is a partially cutaway perspective view of the rear shield and the
outside element for a vehicle as shown in FIG. 1, showing the antenna of
FIG. 2 in place;
FIGS. 4 to 6 are views analogous to FIG. 3 showing various ways in which
the film and the protective screen can be fixed relative to each other and
to the shield; and
FIG. 7 is a close-up view of the shield and the capping of FIG. 1.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
As shown in FIG. 1, a motor vehicle 1 has a rear shield 2 provided with a
protective strip of capping 3.
The vehicle is reversing towards a cone 4 situated at a distance e from the
closest point on the vehicle, i.e. the capping 3.
The capping 3 constitutes a protective screen in the meaning of the
invention, i.e. it covers an antenna of the kind shown in FIG. 2.
The antenna comprises an electrically insulating film 5, e.g. made of VALOX
FR-1 (trademark in the name of GE Plastics) covered on each of its two
faces in an electrically conductive material 6, 7, e.g. a conductive ink.
On the inside, i.e. on its side directed towards the passenger compartment
of the vehicle when the capping 3 is in place, the film 5 is covered by
conductive ink covering its entire surface 6, while on the outside, i.e.
its side facing towards the capping, the film is covered in conductive ink
in its central portion 7 only.
The precise shape of this central portion 7 is easily determined by the
person skilled in the art as a function of the desired antenna
characteristics.
The covering of conductive ink is not constituted by a continuous layer but
presents an open-work pattern forming an array, as can be seen in FIG. 7
where the capping 3 is transparent. In the example of FIG. 7, the openings
8 in the pattern are circular orifices situated at the nodes of a regular
array having a triangular mesh, thereby not only reducing the quantity of
ink needed to implement the antenna, but also co-operating with the
transparent capping 3 to provide a decorative function.
Different appearances can thus be obtained by selecting capping 3 that is
transparent or translucent, colored or not, a film 5 that is tinted, and a
particular pattern made using an optionally-colored conductive material.
In the examples of FIGS. 3 and 7, the film 5 extends between the capping 3
and the shield 2 merely by means of its own stiffness, its outline being
adapted to the narrow volume left empty between said capping and said
shield.
In the example of FIG. 4, the film 5' is stuck to the inside face of the
capping 3', which is preferably opaque and projects from the shield 2' so
as to serve as capping that provides protection against bumps. Such
capping is often bulk-dyed.
In the example of FIG. 5, the film 5" is stuck to the shield 2" in the
bottom of a groove 9" formed to receive the capping 3". In this case, the
capping can be transparent.
In the example of FIG. 6, the shield 2"' has a groove 9"' for receiving a
longitudinal housing 10"' made up of one or two parts, the outside portion
thereof serving as capping 3"' and the inside portion thereof supporting
the film 5"'. This longitudinal housing 10"' presents the advantage of
providing leakproofing against the outside so as to protect the
antenna-constituting film.
Other ways of fixing the film and the capping can equally well be envisaged
by the person skilled in the art.
*
