DE19813782C1 - Access control unit for motor vehicle - Google Patents

Abstract

The access control unit includes a transceiver (1) at the vehicle side for transmitting a request signal and for receiving a response signal. An evaluation unit is provided in the transceiver for comparing the response signal with the anticipated code signal and for controlling door locks (3) dependent on the result. A portable transponder (4) receives the request signal and automatically sends a coded response signal. A switching and control unit (5) releases the request signal and is coupled to one or several detectors (6) and to a light source which are arranged in the area of the door handle (9). The detectors measure the intensity and temporal change of the heat and light radiation in their surroundings. The measured values are transferred to the switching and control unit which provided a first switching signal to the transceiver dependent on a fast intensity change. The request signal is released when receiving the first switching signal and a second switching signal provided by a slow intensity change controls the light source.

Description

The invention relates to an access control device for a motor vehicle in which access to the motor vehicle only if proof of authorization is permitted. It affects also a method for adjusting the sensitivity of the zu aisle control device.

A known access control device (DE 195 16 316 A1) has a vehicle-side transmission and reception unit, which sends out a request signal when required and on Response signal from a portable transponder is waiting (question Answer dialog). If the response signal is received, this in an evaluation unit with an expected signal compared. If the two signals match Door locks unlocked.

The response signal is from the portable transponder returned if it received the request signal Has. To trigger the request signal, the known one Access control device an infrared motion detector, which is arranged in the door handle. If the user is using this movement mel speaks his hand to the door handle the on and triggers the request signal.

The infrared motion detector is however in its function impaired when the ambient temperature and skin temperature rature are very low. Moreover, the Annä is recorded herns of the hand almost impossible if the user hand wearing shoes.

The invention is based on the problem of an access control create trolling device for a motor vehicle in the  the user approaching the motor vehicle early and is reliably recognized. In addition, a method for Setting the sensitivity of the access control device be created, thereby adapting to environmental conditions conditions should be created.

This problem is solved by the features of the invention Claims 1 and 5 solved. The access con trolling device on a switching and control device, by which the request signal is triggered. The switching device is with a pyroelectric and or photosensitive detector. In addition, the assignment aisle control device on a light source by the Switching device is controlled electrically. Detector and Light sources are arranged in the area of the door handle. Of the Detector measures the heat radiation in its environment. The ge measured values are passed on to a switching device tet. The switching device delivers a first switching signal, if the detector has a rapid change in heat radiation notes. Depending on a slow change in heat the light source is switched on or off.

Since the detector heat due to light radiation both in can detect visible as well as in the invisible area, it acts like a light barrier and a proximity sensor equal. Depending on the radiation level detected the detector and how it changes over time adapt the environmental conditions.

Advantageous embodiments of the invention are in the Un marked claims. So can also be a switch be arranged in the door handle through which a manual operation door handle is recognized. The light source and the De tectors are designed so that they both light in the visible transmit or detect in the invisible area can.  

The sensitivity of the detector can be turned on represents that the period of time between approaching the Hand and moving the door handle is measured and dependent its sensitivity is set by threshold values.

Embodiments of the invention are based on the schematic table drawings explained in more detail. Show it:

Fig. 1 is a block diagram of the access control device according to the invention for a motor vehicle and

Fig. 2 is a flow chart for a method for adjusting the sensitivity of the access control device.

An access control device for a motor vehicle has a vehicle-side transmission and reception unit 1 ( FIG. 1), which can transmit a coded request signal via an antenna 2 and can receive a coded response signal. It contains an evaluation unit in which the response signal received is compared with a stored and expected target code signal. If the two signals match, a control signal is generated by which one or more door locks 3 or a trunk lid lock are locked or unlocked.

A portable transponder 4 serves as proof of the authorization to lock or unlock the door locks 3. This transponder 4 automatically sends a coded response signal back after receiving the request signal. The response signal is encrypted and can change its coding with every new transmission (alternating code).

To trigger the request signal, the access control device has a switching and control device 5 , which is electrically connected to one or more detectors 6 , a mechanically electrical switch 7 and a light source 8 .

The detectors 6 are designed as pyroelectric and / or optical detectors (or sensors). They measure the intensity and the temporal change in the heat and / or light radiation in their environment. The detectors 6 are in the area of one or more door handles 9 of the motor vehicle, for. B. on a handle of the door handle 9 or in a door recess 10 , arranged. Likewise, the light source 8 is arranged in the region of the door handle 9 . The door handle 9 can also be a handle for opening the trunk lid (trunk lid).

If the user approaches the door handle 9 with his hand 11 to open the door, it is detected by the detectors 6 on the one hand due to the darkening of the door handle recess 10 and / or on the other hand as a result of the heat radiation emanating from the hand 11 that a hand 11 approaches. This takes place relatively quickly, so that a significant change in intensity can be detected on the detector 6 within about 0.1 s.

The detected intensity is communicated to the switching and control device 5 , which then generates a first switching signal which is sent to the transmitting and receiving unit 1 . Whether the change in intensity is rapid can be determined, for example, by the gradient of the change (slope of the time derivative of the change). As a result of the rapid change, the switching and control device 5 instructs the transmitting and receiving unit 1 with the first switching signal to send out the request signal.

The light source 8 is also arranged in the region of the door handle 9 . It is preferably arranged at the other end against the position of the detectors 6 . If the user reaches with his hand 11 into the door recess 10 , a "darkening" of the detectors 6 is detected with the light source 8 switched on. The light source 8 is particularly switched on when there is little or no extraneous light, e.g. B. at night or in a dark parking garage.

The light source 8 can also emit thermal radiation. Consequently, the heat radiation detected by the detector 6 is weakened by the engagement of a hand 11 (in particular in the case of glove wearers), whereby the approaching of the hand is clearly recognized.

The detectors 6 detect a largely constant light and / or heat without the intervention of the hand 11 . As soon as the user engages in the door handle recess 10 with his hand 11 , the lighting conditions and the heat radiation change very quickly, so that a switching signal is triggered which is fed to the switching and control device 5 .

The light source 8 is switched on or off when the ambient conditions, ie the brightness, change slowly over a longer period of time, e.g. B. over several minutes. Since the detectors 6 constantly measure the light and / or the heat radiation of the environment, a slow change can be detected, a second switching signal can be generated and then the light source 8 can be switched on by the switching and control device 5 if the environment is too dark in the long run or is too cold.

The light source 8 is attached and designed in such a way that it consumes as little energy as possible and provides sufficient light to obtain a noticeable change in intensity on the detector 6 when the hand 11 engages in the door handle recess 10 .

Since the detectors 6 also detect the ambient temperature, the sensitivity of the detectors 6 can be increased at low temperatures. Likewise, a temperature adjustment can be created by a temperature-dependent resistor, which is arranged between the detector 6 and an amplifier (not shown) and through which the signal of the detector 6 is influenced depending on the temperature, then amplified accordingly, and the switching and control device 5 is supplied.

A delayed response of the detectors 6 by a cold environment or cold hands is thus compensated for.

The sensitivity can be set, for example, by the amplifier, which is arranged between the detector 6 and the switching and control unit 5 , by changing its gain.

The light source 8 and the detectors 6 are designed so that they can emit and detect both visible and invisible light. Since infrared light and thus heat radiation from the hand 11 can also be detected, the detector 6 is also a proximity switch. The heat radiation emanating from the hand 11 is detected by the detector 6 .

The light source 8 can be, for example, an LED or an infrared LED (IRED). The detector 6 can be a photodiode. Depending on the version, light rays can be received in the visible and invisible range. As a light source 8 , an optional door handle lighting can be used. Thus, no additional electricity is required for the light source 8 .

The detector 6 can also work as a brightness sensor or light barrier by detecting the darkening as soon as a hand 11 reaches into the door handle 9 . Thus, the movement of the hand 11 is recognized at an early stage in order to carry out the question-answer dialogue between the transmitting and receiving unit 1 and the transponder 4 . If the response signal is then recognized as authorized (successful authentication), the door lock 3 can be unlocked. The question-answer dialog is so quick that the user is not aware of it. The question-answer dialog is then ended as soon as the door handle 9 is actuated mechanically.

The door handle 9 can have a handle which the user depresses with his hand 11 , on which he pulls or presses. Likewise, there can be a flap 12 , as shown in FIG. 1, which is pivoted outwards and upwards to open the door.

When the motor vehicle is in a dark environment, the long-term control of the switching and control device 5 ensures that the light source 8 is switched on. The light source 8 can be a separate light source 8 or an existing lighting of the door handle 9. The detector 6 is illuminated via direct or indirect lighting (reflection), so that darkening takes place when the hand 11 is inserted into the door handle recess 10 . The light source 8 is therefore only switched on when necessary (lack of external lighting in dark surroundings or in extreme cold). Only in these cases is electricity from the vehicle battery provided, which is required in addition to the quiescent current of the switching and control device 5 and the detector 6 . It is thus also recognized whether a glove wearer wants to actuate the door handle 9 .

The geometry or design of the door handle 9 is subordinate. For example, the flap 12 can be used, which is pivoted when the door 11 is opened by hand. A conventional handle can also be present in order to actuate an opening button.

A flap 12 is advantageous in order to largely rule out external influences. In the case of a flap 12 , the detectors 6 are arranged behind the flap 12 in such a way that their detection characteristic is largely limited to the door handle recess 10 . The user must then intervene in the door recess 10 with his hand 11 . If someone walks past the door handle 9 from the outside, this does not lead to a triggering of the request signal.

The range within which heat radiation can still be detected is typically around 5 to 20 cm. The range can also be set up to approximately 1 m and larger if required. However, an excessive range leads to frequent false triggers by uninvolved people or strong light changes in the area surrounding the motor vehicle. On the other hand, the range should be as large as possible, so that the process of the question-answer dialog is completed early and the door lock 3 is unlocked before the door is opened manually. The authorized user should not be irritated by the access control device in his usual procedure of opening the door or should have to wait until the door is unlocked.

The range is advantageously set with the help of the switching and control device 5 according to the sequence of FIG. 2. So that the triggering of the request signal happens in time, the time period can be measured that elapses between the triggering of the detector 6 (first switching signal) as a result of the approach of the hand 11 (hand movement to the door handle 9 ) and the switching of the switch 7 (third switching signal ) as a result of the mechanical movement of the door handle 9. The time between the two switching signals is a measure of the time advantage over a conventional, for example mechanical or capacitive switch for triggering the request signal.

The switch 7 detects the mechanical movement of the door handle 9 when it is operated manually. The time between these two points in time (e.g. time between the rising edges of the generated switching signals) is measured by a timer (timer) in the switching and control device 5 .

If the detected time period (timer status) is less than a minimum threshold MIN, the sensitivity and thus the range of the detectors 6 is increased. It is thus recognized earlier whether a hand 11 is approaching the door handle 9 .

If the duration is greater than a maximum threshold MAX, so the sensitivity or range is reduced. There between (MIN <time period <MAX) the setting of the Emp sensitivity should be maintained.

This ensures that the request signal is not triggered too early but also not too late. If the range and thus the sensitivity is not too great, movements of "foreign bodies", such as passers-by, do not trigger the question-and-answer dialogue incorrectly. In the same way, a long-term drift due to aging of the detectors 6 can be compensated for. As a result, the vehicle battery is protected since the request signal is triggered only when a hand 11 engages in the door handle recess 10 .

Since the detectors 6 can be designed as pyroelectric sensors, they are not too sensitive to optical contamination, as is known to be usual in vehicles. If the detectors 6 are dirty, the sensitivity can be automatically increased in order to compensate for the attenuation of the heat and light radiation by the dirt.

Through the detectors 6 , a time gain of greater than about 100 ms is achieved, for example compared to a conventional capacitive detector, or of approximately 200 ms compared to a conventional mechanical detector. As a result, the request signal is also triggered earlier by this length of time, so that the process of the question-answer dialog is already ended when the hand 11 pulls on the flap 12 , depresses the handle or presses a door button.

So that the detectors 6 and the light source 8 are not always ready for operation, they are switched off after a longer period (several days or weeks) in which they have not detected any movement. So the switching and Steuerein device 5 can go into a rest position. As soon as the door handle 9 is operated manually, this is detected by the switch 7 . The mechanical movement of the door handle then switches the switching and control device 5 on again. Only then does the access control device work again using the detectors 6.

The portable transponder 4 can be arranged on a conventional key handle or a credit card-sized card (smart card or chip card). However, the design of the housing in which the transponder 4 is located is not important for the invention.

A pyroelectric detector 6 has a crystal as the sensor surface. The electrical surface charges at the boundary layer of the crystal become effective due to temperature changes (temperature-dependent polarization) as a result of changes in the spacing of the lattice ions and also in the dipole moment. Changes in temperature are caused by heat and light radiation. Such detectors 6 are already well known and therefore do not need to be explained in more detail.

The switching and control device 5 and the transmitting and receiving unit 1 can also be designed as a single unit and as a microprocessor.

Detectors can also be arranged on the inside of the door in order to cause the door locks 3 to lock when they exit the motor vehicle.

Claims (5)

1. Access control device for a motor vehicle with

• 1. a vehicle-side transmission and reception unit ( 1 ) for transmitting a request signal and for receiving a response signal,
• 2. an evaluation unit in the transmitting and receiving unit ( 1 ) for comparing the response signal with an expected code signal and for controlling door locks as a function of the result of the comparison,
• 3. a portable transponder ( 4 ) for receiving the request signal and automatically returning a coded response signal, whereby the user carrying the transponder demonstrates authorization to lock or unlock one or more door locks ( 3 ),
• 4. a switching and control device ( 5 ) for triggering the request signal, which is electrically connected to one or more detectors ( 6 ) and to a light source ( 8 ) which are arranged in the region of a door handle ( 9 ), the detectors ( 6 ) Measure the intensity and temporal change in the heat and light radiation in their environment and forward the measured values to the switching and control device ( 5 ), which in turn supplies a first switching signal to the transmitting and receiving unit ( 1 ) depending on a rapid change in intensity , so that the request signal is triggered and, depending on a slow change in intensity, supplies a second switching signal to the light source ( 8 ) so that it is switched on or off.

2. Access control device according to claim 1, characterized in that a switch ( 7 ) is arranged in the door handle ( 9 ), which is electrically connected to the switching and control device ( 5 ) and through which a third switching signal as a result of manual actuation of the door handle ( 9 ) is triggered. 3. Access control device according to one of the preceding claims, characterized in that the light source ( 8 ) is an optoelectronic radiation source which emits light rays in the visible region and / or in the invisible region. 4. Access control device according to one of the preceding claims, characterized in that a pyroelectric sensor is used as the detector ( 6 ) which detects light rays in the visible and / or in the invisible region. 5. A method for adjusting the sensitivity of the access control device according to claim 1, characterized in that the period between the occurrence of the first Schalttsi gnals and the third switching signal from the switching and control ereinrichtung ( 5 ) is measured, and when the measured time duration is shorter is as a first threshold (MIN), the detector ( 6 ) is increased in sensitivity, and if the measured time is greater than a second threshold (MAX), the detector ( 6 ) is reduced in sensitivity.