U.S. patent application number 11/357524 was filed with the patent office on 2006-08-31 for seat occupation detection mat.
This patent application is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Stefan Ellinger, Peter Karges, Arnulf Pietsch, Jurgen Zacherl.
Application Number | 20060192417 11/357524 |
Document ID | / |
Family ID | 36284425 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060192417 |
Kind Code |
A1 |
Ellinger; Stefan ; et
al. |
August 31, 2006 |
Seat occupation detection mat
Abstract
A seat occupancy detection mat (1) is proposed with a number of
pressure sensitive sensor elements (2) arranged between two mat
films (8), which is provided with a conductive layer (7) for the
purpose of shielding from electromagnetic interference radiation,
said layer being connected to at least one of the mat films (8, 9),
or being integrated therein.
Inventors: |
Ellinger; Stefan;
(Regensburg, DE) ; Karges; Peter; (Yokohama City,
JP) ; Pietsch; Arnulf; (Regensburg, DE) ;
Zacherl; Jurgen; (Donaustauf, DE) |
Correspondence
Address: |
LERNER GREENBERG STEMER LLP
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Assignee: |
Siemens Aktiengesellschaft
|
Family ID: |
36284425 |
Appl. No.: |
11/357524 |
Filed: |
February 17, 2006 |
Current U.S.
Class: |
297/217.3 |
Current CPC
Class: |
B60R 21/0154 20141001;
B60R 21/01516 20141001 |
Class at
Publication: |
297/217.3 |
International
Class: |
A47C 31/00 20060101
A47C031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 24, 2005 |
DE |
10 2005 008 591.1 |
Claims
1-7. (canceled)
8. A seat occupancy detection mat, comprising: two mat films
disposed in substantially congruent relationship and a conductive
layer provided on at least one of said two mat films; and a
plurality of sensor elements disposed between said two mat
films.
9. The seat occupancy detection mat according to claim 8, wherein
said plurality of elements are pressure-sensitive sensor
elements.
10. The seat occupancy detection mat according to claim 8, wherein
said conductive layer is connected to one of said two mat
films.
11. The seat occupancy detection mat according to claim 10, wherein
said conductive layer is glued to one of said two mat films.
12. The seat occupancy detection mat according to claim 8, wherein
said conductive layer is integrated into one of said mat films.
13. The seat occupancy detection mat according to claim 8, wherein
said conductive layer is connected to a reference potential of said
sensor mat.
14. The seat occupancy detection mat according to claim 13, wherein
said conductive layer is connected via a riveted joint.
15. The seat occupancy detection mat according to claim 14, wherein
said conductive layer is connected via a cable connection.
16. The seat occupancy detection mat according to claim 8, wherein
said conductive layer is connected to a vehicle potential.
17. The seat occupancy detection mat according to claim 8, wherein
said conductive layer is connected to a vehicle chassis.
18. In combination with a motor vehicle, the seat occupancy
detection mat according to claim 8 having said conductive layer
connected to a ground potential of the motor vehicle.
Description
[0001] The invention relates to a seat occupancy detection mat with
a number of sensor elements, especially pressure-sensitive
elements, arranged between two mat films.
[0002] Such seat occupancy detection mats are known from EP 1 491
408 A1 and have been used for some time to control the airbag
and/or the seatbelt restraining means, to indicate that the belt is
not being worn, to adjust lights or also to control the seat
heating in motor vehicles.
[0003] Such a seat occupancy detection mat is integrated into a
motor vehicle seat and an occupancy status of a motor vehicle seat
is determined by means of the seat occupancy detection mat. This
information is transferred to the motor vehicle for further
processing in order to trigger necessary responses in the motor
vehicle, e.g. if the airbag or the other restraining means assigned
to the seat such as the seatbelt for instance, are only activated
if the instantaneous occupancy status requires a triggering of this
type. The seat occupancy detection mats generally comprise a number
of sensor elements arranged between two mat films, e.g. pressure
sensors, which are arranged in a distributed manner in or under the
seat of the motor vehicle seat. An evaluation unit connected to the
seat occupancy detection mat queries the switching status of the
individual sensor elements or a group of sensor elements and
determines an occupancy status of the seat from the respective
switching statuses. If the seat is occupied by a person or an
object, a sensor element or a number of sensor elements is
triggered as a result of the weight exerted on the seat by the
person or the object. The evaluation unit connected thereto detects
whether the seat is occupied and forwards the occupancy status to
the motor vehicle, in particular the air bag controller.
[0004] Since the seat occupancy detection mats are thus also used
in safety-relevant systems, they must satisfy the demand for high
quality standards and must undergo suitable qualification
processes. They are thus also required to ensure a predetermined
qualification in terms of their electromagnetic compatibility (EMC)
and/or their electrostatic discharge (ESD) resistance. Previous
mats do not adequately fulfill the relevant requirements. The aim
of the invention is to overcome this problem.
[0005] This problem is solved inventively in accordance with claim
1 in that at least one of the mat films of the seat occupancy
detection mat is provided with a conductive layer. The resistance
relating to the electrostatic discharge or the shielding of
electromagnetic fields can hereby be improved in a very effective
manner.
[0006] As inferred from the subclaims, in the case of an inventive
seat occupancy detection mat, the conductive layer is
advantageously connected to a mat film, preferably glued thereto.
The conductive layer can however also be integrated into the mat
film, embedded for instance. In this way, the conductive layer can
be formed using a metal wire mesh or a mesh with metallic
particles.
[0007] To discharge a potential forming on the conductive layer
possibly as a result of electrostatic discharge or electromagnetic
radiation, the conductive layer is either connected to the
reference potential of the sensor mat or to a motor vehicle
potential, in particular the motor vehicle chassis. Such a
connection can in this case be a cable connection or a clamping
connection, or in the case of a connection to the reference
potential of the sensor mat, this can simply be a riveted joint by
the sensor mat or a clamping connection on the mat edge, so as to
connect the conductive layer to a conductor into or onto the sensor
mat, which is connected to the reference potential.
[0008] The invention is described in more detail below with
reference to an exemplary embodiment with the aid of figures, in
which
[0009] FIG. 1 shows a seat occupancy detection mat known per se
without an inventive conductive layer,
[0010] FIG. 2 shows a seat occupancy detection mat with an
inventive conductive layer,
[0011] FIG. 3 shows a detailed description of a cross-section
through an inventive seat occupancy detection mat
[0012] FIG. 4 shows a first connection variant of the conductive
layer with reference potential and
[0013] FIG. 5 shows a second connection variant of the conductive
layer with reference potential.
[0014] The seat occupancy detection mat 1 shown in FIG. 1 features
a number of sensor elements 2, which are arranged in a distributed
manner over the seat depending on how the seat occupancy detection
mat 1 is installed into the motor vehicle seat. The sensor elements
2 are partially connected to one another and to an evaluation unit
4 via conductors 3. In this way the sensor elements 2 can be
individually queried by the evaluation unit in a similar manner to
the memory cells in a semi-conductor memory by means of suitable
row and column lines. It is however just as possible to
interconnect individual sensor elements 2 into groups, in order
only to query the response of a sensor element group or of the
entire seat occupancy detection mat. The evaluation unit 4 is
connected to a plug 6 via a cable 5, said plug being able to be
connected to the motor vehicle wiring harness for instance, so as
to make the response of the motor vehicle dependent on the seat
occupancy. The evaluation unit 4 can be connected in particular to
a control device for a passenger protection system, in order to
make the triggering of an airbag for instance dependent on the seat
occupancy.
[0015] FIG. 2 now shows such a seat occupancy detection mat 1,
which is covered, in an inventive manner, with a conductive layer 7
so as to shield electromagnetic radiation.
[0016] FIG. 3 shows a schematic representation of a cross-section
through such an inventive seat occupancy detection mat 1. The seat
occupancy detection mat 1 is formed in this case with an upper and
a lower mat film 8, 9, between which an intermediate layer 10
comprising recesses is arranged. Sensor elements 2 are arranged in
the recesses 11 of the intermediate layer 10, said sensor elements
being formed with a first electrode 12 and a second electrode 13,
with a layer made of pressure sensitive material 14 being formed on
one of the electrodes 12, 13. Both electrodes 12, 13 can however
also be provided with resistance material. The pressure dependency
is then generated by the surface end of the two electrodes, as a
function of the force exerted on the sensor element and the
compression of the two electrodes 12, 13.
[0017] If a force is now exerted on the mat, the layer made of
pressure sensitive material 14 is clamped between the electrodes
12, 13 and forms a pressure-dependent resistance. In order to
detect this pressure-dependent resistance, the electrodes 12, 13 of
the sensor elements 2 are connected to the conductor lines 15 to 18
in the exemplary embodiment illustrated.
[0018] In the exemplary embodiment illustrated, the sensor elements
2 are combined to form two groups of three sensor elements each,
thereby avoiding the need for conductor paths but providing for a
very simple seat occupancy detection. As already detailed, it is
similarly possible to separately query each individual sensor
element 2 by suitably increasing the number of conductor paths.
[0019] To shield the sensor elements 2 and the conductive paths 15
to 19 from electromagnetic interference influences or to protect
them from electrostatic discharge, a conductive layer 7 is arranged
in an inventive manner onto the at least one of the mat films 8, 9,
in the exemplary embodiment, onto the upper mat film 8, said
conductive layer being glued to the mat film for instance. It is
however similarly possible to integrate the conductive layer 7 into
the mat film 8 or 9, or for instance to embed it therein. It is
similarly conceivable to design the conductive layer as a side of a
pocket in which the seat occupancy detection mat is located.
[0020] To discharge potentials forming on the conductive layer 7 as
a result of the electromagnetic inteference radiation, said
conductive layer should be suitably connected to a reference
potential, the reference potential of the seat occupancy detection
mat for instance or also to the motor vehicle potential.
[0021] Two connection variants are shown in FIGS. 4 and 5.
[0022] In FIG. 4, the conductive layer 7 is connected to an
additional conductor 21 with the reference potential of the
evaluation unit 4 via a riveted contact 20 in the seat occupancy
detection mat. According to FIG. 5, the conductive layer 7 can
alternatively also be contacted 5 via a plug contact 22 and be
connected to a reference potential contact 24 in the plug 6 via a
cable 23.
[0023] Both variants illustrated provide for subsequently equipping
of conventional seat occupancy detection mats with a conductive
layer and for a suitable connection to the reference potential.
* * * * *