Note: Descriptions are shown in the official language in which they were submitted.
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239 001 P-WO (Amendments)
INSIDE LIGHTING CIRCUIT FOR A VEHICLE
s Description
The invention relates to a circuit configuration and an
apparatus for the interior lighting of the passenger
area, luggage or cargo area and glove compartment of
io motor vehicles.
In the early days of motor vehicle production, it was
state of the art that the vehicle interior lighting was
manually operated by a manual switch. Since this was
i5 too troublesome as a permanent solution, the manual
switch being especially difficult to locate in the dark,
the problem was posed of automatically switching on the
interior light for entering and leaving the vehicle, the
light being automatically switched off again after the
2o action of entering or leaving the vehicle was completed.
The object was solved by a motion detector, comprising
the door and a door contact as a sensor, which converts
the unavoidable movement of persons entering or leaving
the vehicle, namely operation of the door, into an
2s electrical signal which switches on or off the vehicle
interior light. Today, the widespread state of the art
is a selective switch in the interior of the vehicle
with three positions, door contacts which close on
opening the doors and also the luggage area and glove
3o compartment, and a timer for delayed switching off of
the interior lighting which is triggered when the doors
are closed. Re-triggering of this timer is possible by
renewed opening and closing of the doors. Furthermore,
the ignition system delivers a status signal so that
35 after closing the doors and initiation of the ignition
system, the interior lighting - which remains on for a
period of time - is switched off. Disadvantages of the
prior art hitherto described are that when the selected
switch is set to the "light always off" position, the
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light remains off when the driver opens the vehicle from
outside in the dark. He can neither see the ignition
lock nor the selective switch and must feel around in
the dark with difficulty until he finds the light
switch. A further disadvantage is that the contacts in
the doors, together with the necessary cabling and
plugs, are very expensive, that if the selected switch
is inadvertently left in the "always on" position, the
battery will become discharged at the latest after one
to day and the vehicle would become immobile, and that in
the case of the more commonly-used selective switch
position "switch light on via door contacts" and a door
being inadvertently left open, the battery would also
become discharged after one day at the latest, which is
also the case should a luggage area or glove compartment
also be inadvertently incorrectly closed. Various
solutions are listed in DE 3820829 C2, EP 0622271 A2, EP
0138919 and DE 4407616 A1, although no simple and all-
embracing solution is provided. DE 29518923 U1 limits
2o itself expressly to the illumination of the engine bay
as a method for repelling martens. Furthermore, it is
known prior art for sensors to generate an electrical
signal when the door lock, the remote control or the
central locking are operated, that this signal is
2s supplied to the vehicle interior light and that this
light is switched off or on as a result.
EP 0342345 A2 sees a problem with a type of sensor for
the vehicle interior lighting which comprises, as
3o described above, a motion sensor with the door as an
actuator and a door contact as an end position sensor.
The problem is represented by the cost of the door
contact and its installation. The object is to dispense
with the door contact and its installation. EP 0342345
3s A2 suggests three solutions, each functionally
independent from one another, which do not require each
other. The first one provides that air pressure
fluctuations are recognised by a signal generator on
opening or closing of the door, as the second solution
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an alternating field (e. g. microwave field, ultrasound
field...) generated by a transmitter located in the
vehicle interior is to be disturbed by opening of the
door and/or people entering or leaving the vehicle, this
s disturbance being converted into an electrical switching
signal by means of a receiver and a circuit. The third
independent solution suggests a W transmitter with a W
detector, wherein disturbance of the generated UV field
on opening the door is converted by a sensor and a
to circuit into a switching signal for the vehicle interior
lighting. The hitherto-known prior art is
unsatisfactory, especially the last-mentioned three
solution attempts. In practice, a motion sensor which
generates electrical signals caused by air pressure
15 fluctuations as a result of movement of the door often
delivers an erroneous signal. The suggested motion
sensor, which reacts to interruption of an alternating
field, is only conditionally usable in the form of the
UV motion sensor. W radiation can lead to blindness, a
2o cardboard box on the passenger seat also leads to
disturbance of the UV or ultrasound field in the same
way as opening of the door, and hence would lead to
permanent switching on of the vehicle interior lighting.
Microwaves are continually reflected to and fro by the
2s metal bodywork, penetrate outwards and can e.g. be
reflected back by passing vehicles, causing the interior
lighting to switch on. JPO 08156683 describes a passive
infrared motion sensor which detects the motion of
persons outside the locked vehicle in the vicinity of
3o the door lock, and switches on door lock illumination,
e.g. integrated into the door lock itself. Since only
persons in the vicinity of the door lock on the outside
of the vehicle are detected, persons in the locked
vehicle interior are not detected. In addition, the
35 door lock is only illuminated on the exterior of the
vehicle, illumination of the vehicle interior does not
take place.
The object of the invention is to improve the
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unsatisfactory prior art to the most extensive degree
possible in the simplest manner possible. Since the
prior art already has an inestimable number of solutions
as a result of the many publications, it has at least as
s many failings, the object which includes all failings is
also just as wide in scope. For this reason, and for
the purpose of simplification, the object will
additionally be newly worded: if a vehicle user is
present and moving, the vehicle interior lighting is
to switched on or remains on, if the vehicle user is no
longer present or is no longer moving, the light is
automatically switched off (again) or remains off.
The invention solves the problems with the
15 characterising features of claim 1. An advantageous
expansion is represented by the circuit configuration
according to claim 2. Further advantageous embodiments
result from claims 3 to 24. The invention is
distinguished in that the presence of the vehicle user
2o in the interior of the vehicle is detected directly by
one or more infrared motion sensors, wherein the
hitherto-known timer is triggered or re-triggered for
the time-delayed switching off of the vehicle interior
lighting by this or these motion sensors. In this way,
25 It can be detected if the person enters or leaves the
vehicle, and also when the person fastens their seat
belt, searches for something, etc. It is advantageous
if the infrared motion sensor exclusively recognises the
movement of persons located in the interior of the
3o vehicle when the vehicle is closed. This can take place
by suitable selection of the detection sector of the
motion sensor. With tinted glass, the detection sector
of the motion sensor can be of any size, since only a
fractional portion of the IR radiation from outside can
3s penetrate through tinted glass windscreens. The
detection sector of the IR sensor automatically
increases in size when the door is opened. In this way,
persons in the door opening angle can be recognised and
the vehicle interior lights can be switched on.
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Many embodiments are conceivable within the framework of
the invention. Comfort is increased if the push button
switch is designed as a contact switch. Furthermore, it
5 is conceivable to combine the infrared motion sensor,
the circuit according to the invention, and the timer,
the push button switch and the lights spatially together
in a module which can be located in the roof area.
Furthermore, the combination of IR motion sensor or
io parts thereof, timer and circuit according to the
invention, in an integrated circuit, for example an
ASIC, is also conceivable. Furthermore, in the event
that e.g. persons wish to spend the night in their
vehicle and do not wish to be disturbed by the vehicle
internal lighting under any circumstances, a cover which
is impermeable to infrared light can be provided which
can be pushed over the sensor in order to deactivate it.
It can be desirable for the vehicle interior light to be
switched on before the passive infrared motion sensor is
2o triggered. To this end, the timer is also triggered when
the central locking is moved from the state "locked" to
the state "opened" in order to provide delayed switching
off of the vehicle interior light. Furthermore, the
invention can be realised via software using logic
building blocks such as PALS, GALs, PLDs and/or a
microcomputer. In the event that the infrared sensor
with the described screen is deactivated, or in the case
of extreme climatic conditions where the vehicle
interior temperature is close to that of the human body,
3o even at night, and where the infrared motion sensor is
not activated, it can nevertheless be desirable to
provide a possibility for lighting the vehicle interior.
This is possible by the timer having the facility to be
triggered for time-delayed switching off of the vehicle
interior lighting via the manual switch as described
above. Here, the logic circuit provides that when the
timer has timed out and the trigger signal of the manual
switch is received, the holding element, as described
above, which is provided for storing the switch input
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remains locked for manual input and that merely the
timer is triggered. The holding element is only
released for entry by the then-triggered timer when the
switch signal has dropped out. Hence the vehicle user
s can illuminate the vehicle interior for the specified
time of the timer by operating the manual switch when
the infrared motion sensor is deactivated. The
specified time of the timer is here preferably 25
seconds. The light can be switched off before the timer
io has dropped out by operating the manual switch, as
otherwise the holding element for the push button switch
is released by the timer for entry. Furthermore,
comfort is increased if the area of the door sills is
illuminated by lamps disposed in the lower area of the
is doors. Furthermore, comfort is increased if the
switching on or switching off of the vehicle interior
lighting is dimmed, that is, if the lights are not
switched on and off immediately but are rather gently
increased or decreased in intensity.
Furthermore, it is possible that the vehicle interior
lighting is only switched on when a provided brightness
sensor recognises that brightness has dropped below a
defined level. If a plurality of infrared motion
2s sensors are provided in a vehicle interior, according to
the invention, it is advantageous, based on the low
number of parts and the high number of items in
production, if circuit configurations are used which are
identical, and which can be combined into a master
3o circuit by means of e.g. master-slave switching or
external circuitry. As an example, when using two IR
motion sensors, in each case the evaluation circuit of
the passive IR motion sensor, the logic circuit, the
holding element, the dimmer control, etc. can be on two
s5 identical ASICs. The first ASIC can serve as master,
the second as SLAVE. With the first ASIC, for example,
the holding element can be connected to a push button
switch, on the second ASIC this holding element can,
e.g., be deactivated by connecting to GROUND. When only
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one PIR motion sensor is used, it is also advantageous
that individual functions can be deactivated by external
switching, depending on the model politics of the
vehicle manufacture. Any number of possibilities are
s feasible according to the laws of logic operation.
Higher unit numbers of identical electronic components
and/or integrated circuits can be realised at
correspondingly low unit costs as a result of these
standardised components. Furthermore, draining of the
io battery is securely prevented by the circuit, according
to the invention, as the battery need no longer be
"protected" by its own circuit for the glove compartment
interior light. The glove compartment interior light
can be switched parallel to the vehicle interior light.
i5 A separate switch for the glove compartment interior
light is then no longer necessary. Furthermore, it is
advantageous, in order to keep the number of infrared
motion sensors low, to use optical light conductor
systems to collect IR light from areas in the vehicle
2o which cannot directly be seen by a PIR sensor in its
defined position, to collect and/or divert and/or convey
the IR light so that it can reach the IR sensor. Here,
all known optical means can be used such as lenses,
mirrors, facetted mirrors, Fresnel lenses, optical fibre
z5 cables, etc. comprising all materials known in the field
of optics, and the physical laws of reflection,
refraction, diffraction and polarisation.
This embodiment of the invention is described in one
3o example: a module is disposed on the vehicle roof
between the front seats, containing PIR motion sensors,
push button switch, lights, logic circuits, according to
the invention, etc. An optical system is provided in
the module which collects IR light from all areas which
35 can be reached by the module in a straight line.
Furthermore, facetted mirrors are disposed on the
vehicle roof in the housings for the rear seat reading
lamps, similar to a shed roof, which divert IR light
from the area of the rear seat, optionally collecting
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it, in such a way that the light can be detected by the
IR sensor in the module. In the case of utility
vehicles, such a diverting element is provided on the
roof above the load bay, optionally with a light-
s collecting function, which deflects the IR light from
the luggage area in such a way that it can reach the IR
sensor. In the case of limousine models, the IR light
in the luggage area is also detected and/or collected
and is brought into the vehicle interior by means of an
io optical fibre. The IR light enters the vehicle interior
in such a position so that it can be detected by the IR
sensor. Strong segmentation of the detection sectors is
advantageous with every form of light deflection in
order to provide the PIR motion sensor with a sufficient
15 reception signal. Furthermore, it is expedient to
dispense with the luggage area contact, which is no
longer necessary, and to connect the luggage area
interior lighting in parallel with the remaining vehicle
interior lighting. In the case of cabriolets, it is
2o advantageous if the IR motion sensor is entirely
deactivated when the roof is open, or that it has a
reduced detection sector so that persons outside the
vehicle are not detected. Furthermore, it is
advantageous for use in certain climatic zones if the IR
2s sensor can be cooled by means of a Peltier element.
Advantageously, the Peltier element is switched on if a
provided temperature detection system detects a
temperature of the IR sensor above a defined
temperature, and the brightness sensor, as described
3o above, determines that the brightness in the vehicle is
insufficient. Here, it is advantageous if the Peltier
element is also used as a temperature sensor with an
alternating cooling, measuring and, optionally, pause
cycle. It is furthermore expedient, for reasons of
35 energy conservation, if those components with high
energy consumption are only provided with current after
detection of a vehicle user, with the described
invention.
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Such a SLEEP mode of the circuit is very easy to realise
with a CMOS-based PIR motion sensor. Furthermore, it is
expedient for future expansions to provide additional
trigger inputs for triggering timers. In addition,
s comfort is increased if the individual lamps in the
vehicle can be switched separately. The invention is
also described with reference to the embodiment example
in Figure 1. Connections, supply voltages, pull
resistances, capacitors for run-time synchronisation
io which are not required for comprehension are not
illustrated here for reasons of simplicity. The status
signal of the ignition Z is present both at the data
input of the D-flip-flop (1) and also at one input of
the NEXOR gate (2). The negative output of the D-flip-
15 flop (1) is present at the other input of the NEXOR gate
(2). The output of the NEXOR component is connected
with both the clock input of the D-flip-flop (2) and
also with one input of the OR gate (6). Every status
alteration of the status signal of the ignition Z leads
2o to parity at the input of the NEXOR gate and hence the
output of the NEXOR gate (2) goes high and the D-flip-
flop (1) is clocked. The negated data output of the D-
flip-flop (1) is inverted by the transfer of the current
state of the ignition, the parity of the input signals
2s at the NEXOR gate (2) is then no longer present and the
output of the gate then returns to LOW. The push button
switch (3) is connected to a voltage which logically
corresponds to HIGH. Furthermore, it is connected to
one input of the AND gate (7). The other input of the
3o AND gate (7) is connected with the non-negated data
output of the timer (7). The output of the AND gate (7)
is connected with the clock input of the D-flip-flop (4)
and is only logically HIGH when the timer (7) has not
yet timed out and the push button switch (3) is pressed.
35 At the D-flip-flop (4), the negated data output is
supplied back to the data input so that the contents of
the D-flip-flop alter with each LOW-HIGH transition at
the clock input. The non-negated data output of the D-
flip-flop (4) is connected with an input of the NEXOR
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component (5), the other input of which is connected to
the status signal of the ignition Z. Hence it is always
logically high at the output of the NEXOR component (5)
if the ignition is off and the D-flip-flop (4) is not
s set via the push button switch (3), or when the ignition
is on and the D-flip-flop (4) is set. The reset input
of the D-flip-flop (4) is connected to the output of the
OR component. Hence an alteration in the status of the
motor ignition, that is, each HIGH-LOW transition and
to LOW-HIGH transition, leads to resetting of the D-flip-
flop (4). The timer for delayed switching off of the
vehicle interior lights (7) is, according to the
invention, no longer triggered or re-triggered by the
door contacts, but rather by the signal IR of an
infrared motion sensor. The non-negated data output of
the timer (7) is connected with the SET input of the D-
flip-flop (10). As long as the timer runs, the D-flip-
flop (10) is set. The non-negated data output of the D-
flip-flop (10) is connected to the non-negated input of
2o the AND component (9). The other, negated, data input
of the AND component (9) is also connected to the non-
negated data output of the timer (8). If the timer (8)
drops out after a specified time, a logical HIGH
momentarily results at the output of the AND component
(9), which resets both the D-flip-flop (10) via its
reset input and also, via the OR component (6), the D-
flip flop (4) via its reset input. The non-negated
signal of the timer (8) is present at one input of the
AND gate (11), the output of the NEXOR gate (5) is
3o connected to the other input, the signal L is guided on
an amplification circuit according to the current prior
art, not illustrated, at the output of the AND component
(11) via which the interior lighting is finally switched
on. If the timer (8) is triggered by the infrared
motion sensor, and if the ignition is off and the
holding element (4) is not set by the push button
switch, then the lighting is switched on, also if the
timer (8) is not yet expired, the ignition is on and the
holding element (4) is set by the push button switch
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(3) .
As a variant of the logic circuit as described, the
negated output signal of the D-flip-flop (1) can be
s present at the data input of the D-flip-flop (1) instead
of the signal from the ignition.
An advantage of the invention is that the vehicle user
has light in the vehicle, with the ignition being off,
to at least until they have left the vehicle. If the user
wishes to turn off the light for whatever reason whilst
they are in the vehicle, they need only press the button
(3) once. The light remains off for as long as the user
is in the vehicle. If required, the light also remains
is off when the doors are opened. If the user returns to
the vehicle after some time which is longer than the
running time of the timer, the light immediately
switches on when IR motion detectors detect said user.
As a further advantage, the light is inevitably switched
20 off after the timer times out when the vehicle user is
not present. This ensures that the battery is not
drained. Furthermore, the use of expensive door
contacts is no longer required.