EP0955431B1 - Security system for an opening of a motor vehicle - Google Patents

Description

The invention relates to a security system for an opening of a motor vehicle.

The invention relates more particularly to a security system for an opening of a motor vehicle, of the type in which the leaf is held in the closed position by a lock that is controlled through a handle, and the type in which the security system includes means for detecting the presence of a hand of a user near the handle.

Such a system is for example described in the FR-A-2.733.783. The system described in this document proposes to use as a means of detecting presence of the hand an infrared radiation sensor. This sensor "observes" an area of the space around the lever of detection so that when a user approaches his hand of the handle, the infrared radiation emitted by the hand is collected and analyzed by the sensor which is then likely to transmit ordering information to a electronic module of the security system.

Using an infrared radiation sensor however, is unsatisfactory. Indeed, the radiation infrared emitted by the user's hand may vary from very important way according to many parameters. In particular, when the user wears gloves, the emission infrared hand can be significantly reduced to the point of becoming undetectable.

In this way, the security system equipped with such sensor does not have enough reliability guarantee in the detection of the hand to ensure this function in all possible situations of common use of a vehicle.

In the document DE-A-196.17.038, it is described a security system in which the detection means of the hand use the principle of varying capacity in a capacitor whose armatures are constituted on the one hand by the sheet metal panel of a door and secondly by a metal element integrated into a gripping element of the handle. The hand, coming in between the two frames, modifies the capacity of the capacitor thus formed.

The principle of this device is therefore to detect a capacitor capacity variation, which is generally performed by integrating this capacitor into a oscillating electronic circuit whose frequency is checked oscillation. Capacitor capacity variation, and therefore the presence of the hand, is detected by a variation of the oscillation frequency of the circuit.

The object of the invention is to propose a novel design of the means of detection of the presence of the hand close to the handle that are both inexpensive to implement and that allow a particular detection performing on the one hand in terms of sensitivity and, on the other on the other hand, in terms of resistance to parasitic external influences.

• une antenne d'émission sur laquelle est appliquée une tension périodique ;
• une antenne de réception ;
• un circuit de détection muni de moyens de mesure de la différence de potentiel entre l'antenne de réception et une masse électrique, et muni de moyens de comparaison de l'amplitude de la variation de ladite différence de potentiel par rapport à une valeur de référence de l'amplitude.

For this purpose, the invention proposes a security system for an opening of a motor vehicle, of the type in which the opening is held in the closed position by a lock which is controlled by means of a handle, and of the type in which security system comprises means for detecting the presence of a hand of a user near the handle, characterized in that the means for detecting the hand comprise:

• a transmitting antenna to which a periodic voltage is applied;
• a receiving antenna;
• a detection circuit provided with means for measuring the potential difference between the receiving antenna and an electrical ground, and provided with means for comparing the amplitude of the variation of said potential difference with respect to a reference value amplitude.

• la valeur de référence d'amplitude est fixe, et les moyens de détection émettent une information de détection lorsque l'amplitude de la variation de ladite différence de potentiel devient inférieure à la valeur de référence d'amplitude ;
• la valeur de référence d'amplitude est égale à une valeur de l'amplitude de la variation de ladite différence de potentiel filtrée au travers d'un filtre présentant un temps de retard, et les moyens de détection émettent une information de détection lorsque la différence entre l'amplitude de variation de ladite différence de potentiel et la valeur de référence d'amplitude excède un seuil prédéterminé ;
• la fréquence de la tension périodique est fixe et comprise entre un kilohertz et un mégahertz ;
• les antennes d'émission et de réception sont formées par deux éléments conducteurs intégrés dans la poignée ;
• l'une au moins des deux antennes est intégrée dans un élément de préhension de la poignée ;
• le système comporte des moyens de reconnaissance par ondes électromagnétiques d'un identifiant porté par un utilisateur autorisé, les moyens de reconnaissance comportent un circuit de reconnaissance relié à un émetteur et/ou à un récepteur agencé à proximité de la poignée, et l'une des antennes des moyens de détection est constituée par l'émetteur et/ou le récepteur des moyens de reconnaissance ;
• le système de sécurité comporte des moyens de commutation qui permettent de relier sélectivement l'émetteur et/ou le récepteur au circuit de détection ou au circuit de reconnaissance ;
• les moyens de commutation sont commandés pour relier l'émetteur et/ou le récepteur au circuit de reconnaissance lorsqu'un utilisateur a été détecté par les moyens de détection.

According to other features of the invention:

• the amplitude reference value is fixed, and the detection means emits detection information when the amplitude of the variation of said potential difference becomes smaller than the amplitude reference value;
• the amplitude reference value is equal to a value of the amplitude of the variation of said filtered potential difference through a filter having a delay time, and the detection means transmit a detection information when the difference between the amplitude of variation of said potential difference and the amplitude reference value exceeds a predetermined threshold;
• the frequency of the periodic voltage is fixed and between one kilohertz and one megahertz;
• the transmitting and receiving antennas are formed by two conductive elements integrated in the handle;
• at least one of the two antennas is integrated in a gripping element of the handle;
• the system comprises means for recognition by electromagnetic waves of an identifier carried by an authorized user, the recognition means comprise a recognition circuit connected to a transmitter and / or to a receiver arranged near the handle, and one antennas of the detection means is constituted by the transmitter and / or the receiver of the recognition means;
• the security system comprises switching means for selectively connecting the transmitter and / or the receiver to the detection circuit or to the recognition circuit;
• the switching means are controlled to connect the transmitter and / or the receiver to the recognition circuit when a user has been detected by the detection means.

• les figures 1 et 2 sont des vues schématiques en perspective illustrant deux modes de réalisation de l'intégration des moyens de détection selon l'invention dans une poignée ;
• la figure 3 est une vue schématique illustrant les différents composants formant le circuit de détection selon l'invention ;
• la figure 4 est un diagramme illustrant le fonctionnement du circuit de détection dans un premier mode de réalisation à seuil de détection fixe ; et
• les figures 5 et 6 sont des diagrammes similaires à celui de la figure 4 illustrant un second mode de réalisation de l'invention dans lequel le seuil de détection est variable.

Other features and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

• Figures 1 and 2 are schematic perspective views illustrating two embodiments of the integration of the detection means according to the invention in a handle;
• Figure 3 is a schematic view illustrating the various components forming the detection circuit according to the invention;
• FIG. 4 is a diagram illustrating the operation of the detection circuit in a first embodiment with a fixed detection threshold; and
• Figures 5 and 6 are diagrams similar to that of Figure 4 illustrating a second embodiment of the invention wherein the detection threshold is variable.

FIGS. 1 and 2 show a handle 10 of motor vehicle, for example intended to be mounted on a vehicle door to allow opening.

For example, the handle 10 is a handful of type "refrigerator" intended to be raised by to an outer sheet panel (not shown) of the opening of the vehicle. The handle 10 thus comprises, the outside of the opening, a gripping lever 12 which is movable between a rest position illustrated in FIGS. 2 and an open position (not shown) in which the lever 12 is spread outwardly relative to the panel of sheet metal by the hand of the user, and wherein the lever 12 actuates a lock mechanism (not shown), possibly through a transmission linkage (not shown) To do this, the user engages his hand between the lever 12 and the sheet metal panel, thus acting on a rear surface 14 of the lever 12.

The handle 10 also includes a latch 16 which is arranged outside the sheet metal panel, which is fixed and which has a bore 18 for receiving, for example a rotary latch to prevent the actuation of the lock.

The handle 10 also has parts 20, 22, which are arranged on the inside by compared to the external sheet metal panel, which allow in particular fixing the handle on the opening and the connection of the handle 10, and more particularly of its lever 12, with the lock mechanism that the handle is intended to order.

According to the invention, the security system comprises means to detect the presence of the hand of a user when it arrives close to the handle, but before there is actually contact between the hand and the handle.

Indeed, the security system according to the invention will be advantageously implemented within the framework of a system of security comprising means for remote identification of the user. In such a system, the user wears a identifier, for example a transponder which, in response to a interrogation signal sent by the security system, returns an identification code specific to this transponder. If the code identification code re-transmitted by the transponder corresponds to code expected by the security system, the latter causes unlocking the opening of the vehicle. The user can then open the opening simply by acting on the handle 10, without first having to engage a key in the lock and without having to manipulate a remote control.

The exchange of information between the system of security and the transponder worn by the user make generally uses high electromagnetic bonds frequency that consume a quantity of energy not negligible and constitute a source of "pollution" electromagnetic. It is therefore desirable that the process identification is not implemented continuously when the vehicle is locked.

To do this, it has already been proposed not to trigger the identification process only when the user starts to actuate the lever 12 of the handle 10, the latter comprising for example a switch triggering the process Identification.

However, the processes of identification and unlocking require a not insignificant time which, if they are triggered only when the user already has control over the handle, generates a latency period during which the user can handle the handle without causing the opening of the opening. This latency is usually perceived in an unpleasant way.

Also, it appeared the need to provide the system with security means of detection of the approach of the hand of the user who can trigger the process identification and unlocking before the user has actually grabbed the handle 10.

According to the invention, the detection means of the presence of the hand essentially comprise an antenna 24 and a receiving antenna 26 which, in the two embodiments of the invention illustrated in FIGS. and 2, are integrated in the handle 10.

In the embodiment of FIG. 1, the antenna 24 and the receiving antenna 26 are both made in the form of a metallic conductive wire; and they are arranged longitudinally, parallel to one another, in the lever 12 of the handle 10.

On the contrary, in the embodiment of the FIG. 2, the transmitting antenna 24 is made using a fixed metal part, which may for example be constituted by a tubular jacket in which is intended to be received on lock. The receiving antenna 26 is constituted by transmitter and / or receiver of a recognition circuit by which the security system performs the recognition and the identification of the transponder carried by the user.

In the exemplary embodiment illustrated in FIG. the transmitter or receiver of the recognition circuit that is realized in the form of a winding integrated in the lever 12 and which is therefore also used to ensure the detection of the approach from the hand.

In both cases, the transmitters 24 and receiving 26 are connected to a detection circuit 28, plus particularly visible in Figure 3, which comprises two separate parts.

As can be seen in Figure 3, the circuit of detection 28 includes a generator 30 which applies to the transmitting antenna 24, possibly by a circuit amplification 32, a periodic potential.

The reception antenna 26 is connected, possibly by a second amplification circuit 34, to means 36 of measuring and comparing the signal received by the antenna 26.

Indeed, we observe that when the antenna 24 is subject to the periodic potential by the generator 30, it appears in the receiving antenna 26 a corresponding signal of the same frequency. Preferably, will use a voltage whose frequency is substantially range from 1KHz to 1MHz.

Of course, the level of the signal received by the antenna 26 is lower than that transmitted by the antenna issue 24.

According to the invention, the means 36 for measuring and comparison of the detection circuit 28 are able to measure the amplitude A of the variation of the potential difference between the receiving antenna 26 and an electrical reference, for example the electric mass of the vehicle.

When the user approaches his hand from the handle 10, there appears to be a significant decrease in the amplitude A of this potential difference.

Also, to detect the presence of a hand near the handle 10, it is sufficient for the measuring and comparing means 36 to compare the amplitude A of the potential difference received at the receiving antenna 26 with a reference amplitude A _ref to deduce the presence or absence of the hand and to possibly transmit a hand detection information.

The invention can be implemented using either a reference amplitude A _ref fixed or a reference amplitude A _ref variable.

In the diagram of FIG. 4, the operation of the detection circuit 28 is illustrated in the case where the reference amplitude A _ref is fixed. In this case, the detection circuit 28 transmits hand detection information when the measuring and comparing means 36 measure an amplitude level A of the signal received by the receiving antenna 26 which becomes smaller than the amplitude. reference A _ref .

On the contrary, it is possible to use a reference amplitude A _ref variable, this in particular in order to take account of a gradual variation of the coupling characteristics between the transmitting antenna 24 and the receiving antenna 26, variation which may for example be due to a change in atmospheric conditions.

In this case, it is possible, for example, to use as reference amplitude A _ref a filtered value of the amplitude A of the signal received by the reception antenna 26. For this purpose, a filter having a relatively long delay time will be used. for example of the order of a few seconds.

Thus, when there is a very gradual and very slow variation of the amplitude level A of the variation of potential difference at the level of the reception antenna 26, the reference amplitude A _ref changes with the instantaneous level of the amplitude A such that the difference between the instantaneous amplitude level A and the reference level _ref remains in all cases relatively low. In this case, the detection circuit 28 does not generate hand detection information and therefore interprets this evolution of the amplitude level A as resulting from a slow evolution of the environment of the handle 12, independent of the presence of a user.

On the contrary, when the user approaches his hand, he usually does so at a relatively high speed. As a result, the instantaneous level A of the amplitude of variation of the potential difference at the level of the receiving antenna 26 drops rapidly, as illustrated in FIG. 6. However, the reference amplitude A _ref being obtained by filtering the instantaneous level of amplitude through a filter with a high delay time, a large difference is created between the instantaneous amplitude level A and the reference amplitude A _ref , the detection circuit 28 being then able to interpret this strong difference as being the result of the approach of the hand of a user. When this difference exceeds a predetermined threshold, the detection circuit 28 generates information for detecting the presence of the hand which is transmitted to the security system, which can then trigger the recognition process of the identifier worn by the user and , if necessary, trigger the unlocking process of the opening.

In the case where one of the transmit antennas 24 or of reception 26 is constituted by an element forming transmitter / receiver for the recognition circuit, advantageously provide a switching system by which said element will be alternately connected to the circuit of recognition or detection circuit. 28. Indeed, two circuits do not have to be used at the same time because that the recognition process is only implemented when a user has been previously detected by detection means.

In the exemplary embodiments illustrated, the antennas 24, 26 are carried by the handle 10, which is particularly advantageous in terms of assembly time of the system on the vehicle. However, the invention can also be implemented in a security system in which the antennas are carried for example by the opening of the vehicle.

Similarly, the detection circuit 28 can be indifferently arranged or not on the handle.

Claims (9)

1. Security system for a motor vehicle door, of the type in which the door is held in the closed position by a lock which is controlled by means of a handle (10) and of the type in which the security system comprises means for detecting the presence of the hand of a user close to the handle (10),
   characterised in that the means of detecting the hand comprise:

   a transmission antenna (24) to which a periodic voltage is applied;

   a reception antenna (26);

   a detection circuit (28) provided with means of measuring the potential difference between the reception antenna (26) and an electrical earth, provided with means of comparing the amplitude (A) of the variation in the said potential difference with respect to a reference value (A_ref) of the amplitude.
2. Security system according to Claim 1, characterised in that the amplitude reference value (A_ref) is fixed and in that the detection means (36) transmit detection information when the amplitude (A) of the variation in the said potential difference becomes less than the amplitude reference value (A_ref).
3. Security system according to Claim 1, characterised in that the amplitude reference value (A_ref) is equal to a value of the amplitude (A) of the variation in the said potential difference filtered through a filter having a delay time, and in that the detection means (36) transmit detection information when the difference between the amplitude (A) of the variation in the said potential difference and the amplitude reference value (A_ref) exceeds a predetermined threshold.
4. Security system according to any one of the preceding claims, characterised in that the frequency of the periodic voltage is fixed and lies between one kilohertz and one megahertz.
5. Security system according to any one of the preceding claims, characterised in that the transmission (24) and reception (26) antennae are formed by two conductive elements integrated in the handle (10).
6. Security system according to Claim 5, characterised in that at least one of the two antennae (24, 26) is integrated in a gripping member (12) of the handle (10).
7. Security system according to any one of the preceding claims, characterised in that the system comprises means of recognising by electromagnetic waves an identifier carried by an authorised user, in that the recognition means comprise a recognition circuit connected to a transmitter and/or to a receiver arranged close to the handle, and in that one (26) of the antennae of the detection means consists of the transmitter and/or the receiver of the recognition means.
8. Security system according to Claim 7, characterised in that the security system comprises switching means which selectively switch the transmitter and/or the receiver (26) to the detection circuit (28) or to the recognition circuit.
9. Security system according to Claim 8, characterised in that the switching means are controlled so as to connect the transmitter and/or the receiver (26) to the recognition circuit when a user has been detected by the detection means.

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