Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-07-27
2003-04-29
La, Anh (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C280S735000, C307S009100
Reexamination Certificate
active
06556137
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a passenger detecting system and an air bag apparatus. More particularly, the present invention relates to a technique for detecting the presence or absence of a passenger in a seat of an automobile and for controlling the expansion of an air bag of an air bag apparatus.
2. Description of the Related Art
Generally, an air bag apparatus is an apparatus to ease the impact which a driver and passengers receive upon collision of an automobile. The air bag apparatus has been necessary for the safety of the automobile. Recently, the air bag apparatus has been installed at the passenger side in addition to the driver's side.
For example, as shown in
FIG. 1A
; a first conventional air bag apparatus is composed of a driving seat side squib circuit, a passenger seat side squib circuit, an electronic acceleration sensor GS as a collision detecting sensor, and a control circuit CC. The driving seat side squib circuit includes a series circuit of a safing sensor SS
1
; a squib SQ
1
, and a switching element SW
1
such as an electric field effect type transistor. The passenger seat side squib circuit includes a series circuit of a safing sensor SS
2
, a squib SQ
2
, and a switching element SW
2
such as an electric field effect type transistor. The control circuit CC has a function to detect collision of an automobile in accordance with the output signal of the electronic acceleration sensor GS and to supply a signal to the gates of the switching elements SW
1
and SW
2
.
According to the first conventional air bag apparatus, in the event of an automobile collision, the switch contacts of the safing sensors SS
1
and SS
2
are closed in response to the relatively small acceleration. Then, the squib circuits on the driving seat side and the passenger seat side are set to their operable states. When the control circuit CC reliably determines the collision of the automobile in accordance with the signal from the electronic acceleration sensor GS, squib control signals are supplied to the gates of the switching elements SW
1
and SW
2
to set to the ON state. By this, a current flows through each squib circuit. As a result, the squib circuits SQ
1
and SQ
2
are heated and the air bags on the driving seat side and the passenger seat side are developed, so that the driver and passenger are protected from the impact of the collision.
In the first conventional air bag apparatus, the air bag is expanded out upon collision of the automobile irrespective of whether or not a passenger is present in the passenger seat or of the size of the passenger. For example, when an adult passenger is present in the passenger seat, the passenger will be protected upon the collision as mentioned above. However, when the passenger is a child, since a child is shorter than an adult, the head position of the child is low than that of the adult. Therefore, there is a concern of injury to the child during expansion of the air bag a child, it is sometimes desirable that the air bag is not expanded even if the automobile collides.
Therefore, a second conventional air bag apparatus as shown in
FIG. 1B
has been proposed to cope with such a problem. In this air bag apparatus, a sensor SD is further provided to detect whether or not a passenger is present in a passenger seat. The control circuit CC determines whether or not a passenger is present in the passenger seat in accordance with a detection signal of the sensor SD, and selectively sets the air bag to either the expansion allowable state or the expansion inhibited state in accordance with the determined result.
In particular, a passenger detecting system using a weight sensor such as the sensor SD is proposed in which the determination of whether the passenger is an adult or a child is performed in accordance with the weight of the passenger as measured by the weight sensor. Also, a passenger detecting system is proposed in which an image of the passenger in the passenger seat is picked up by a camera and a determination of whether the passenger is an adult or a child is performed through image processing.
According to the former system, a rough determination of whether the passenger is an adult or a child is possible. The air bag is set to either the expansion allowable state or the expansion inhibited state in accordance with the determination result. Thus, the unexpected situation in a collision of an automobile can be avoided. However, there is a problem of a lack of accuracy, because the difference in weight between individuals is large and a child can be sometimes heavier in weight than an adult.
Also, according to the fatter system, the determination of whether or not a passenger is present in the seat, and the determination of whether the passenger is an adult or a child can be quite correctly performed. However; there is a problem in that a processor for determining the above-described information becomes complicated and expensive, because the imaging data picked up by the camera needs to be subjected to image processing and a comparing process with various image patterns.
In conjunction with the above, a passenger detecting system to detect the presence or absence of a passenger in the passenger seat are proposed in various systems. In Japanese Laid Open Patent Application (JP-A-Heisei 4-46843), Japanese Laid Open Utility Model Application (JP-U-Heisei 3-52266), Japanese Laid Open Patent Application (JP-A-Shown 61-113527), a passenger detecting system in which a weight sensor is incorporated inside the seat is disclosed. Also, Japanese Laid Open Patent Application (JP-A-Heisei 9-509118)discloses a passenger detecting system in which electrodes are arranged in a seat section and a back supporting section of a seat and an-oscillation circuit is connected between the electrodes or between the electrode and the chassis of a vehicle.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a passenger detecting system in which the presence or absence of a passenger in a seat can be accurately detected irrespective of an ambient temperature.
Another object of the present invention is to provide a passenger detecting system in which the presence or absence of a passenger in a passenger seat can be accurately detected without influence by the position of the passenger.
Still another object of the present invention is to provide an air bag apparatus which includes the above passenger detecting system and in which an air bag can be controlled in accordance with detected result.
In order to achieve one aspect of the present invention, a passenger detecting system includes an antenna electrode, a signal generating circuit, a detecting circuit, and control circuit. The antenna electrode is provided in a seat to be occupied by a passenger. The signal generating circuit generates and supplies a supply signal to the antenna electrode through a resistor such that an electric field is generated around the antenna electrode. The detecting circuit includes the resistor, and detects direct current data signal from a line voltage associated with a voltage drop by the resistor, wherein the line voltage changes depending upon an object on the seat. The control circuit determines from the detected direct current data signal, whether or not a passenger is present on the seat and whether the passenger is an adult or a child.
The passenger detecting system may further include an amplitude control circuit for detecting an amplitude of the supply signal and adjusting the amplitude to a predetermined value based on the detected amplitude. The supply signal may be an alternating current signal having a frequency of about 120 KHz and a voltage in a range of 5 to 12 V.
The detecting circuit may include a converter for converting the line voltage of alternating current into a direct current signal. In this case, the detecting circuit further includes an impedance converting circuit provided between the resistor and the converter and having a high impedance on an input sid
Baba Satoshi
Oka Yoshitaka
Dickstein Shapiro Morin & Oshinsky LLP.
La Anh
NEC Corp.
LandOfFree
Passenger detecting system and air bag apparatus using the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Passenger detecting system and air bag apparatus using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Passenger detecting system and air bag apparatus using the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3023624