[0001] The invention is in the field of lighting equipment. In particular, the invention
relates to a lighting device including a sensor for monitoring an environment of the
lighting device.
[0002] Sensors are commonly used in lighting equipment to control the lighting equipment
based on detected events or changes in their environment. Motion detectors and microphones
are used to detect the presence of a person, for example.
[0003] EP 3 220 042 A1 discloses a lighting device (luminaire) comprising a LED module, a cup-shaped reflector
for reflecting the light emitted by the diffusor and a passive infrared sensor (PIR
sensor) for motion detection, wherein the PIR sensor is mounted on a circuit board
of the LED module and a window is integrated into the reflector to guide infrared
radiation to the PIR sensor.
[0004] Since the PIR sensor is directed to the open side of the cup-shaped reflector, a
person looking into the opening (direct line of sight) can easily see the sensor or
its lens. While infrared or PIR-sensors often affect aesthetics of the lighting device,
visible microphones, on the other hand, can make a person feel like they are being
overheard. Further, additional electronic components are usually required to integrate
the sensor function into a luminaire.
[0005] It is an object of the present invention to provide an apparatus and a method, which
reduce the above problems. In particular, an object of the present invention is to
provide a lighting device with an unobtrusive sensor with low efforts and costs.
[0006] This object is achieved by a lighting device according to the enclosed independent
claim 1. Advantageous features of the present invention are defined in the corresponding
dependent claims.
[0007] According to the present invention, a lighting device comprises a housing, at least
one component elastically connected to the housing and at least one sensor configured
to detect vibrations in an environment of the lighting device to be monitored by detecting
a movement of the at least one component relative to the housing caused by the vibrations.
[0008] With the present invention, existing components, originally intended/designed only
to provide light for illumination, are additionally used to detect vibrations. Since
the sensor consists at least in part of components of the lighting device (luminaire),
no or few additional components are required to provide the sensor function and the
sensor as such is hardly noticed.
[0009] The sensor can be used to detect a vibration that propagates as an acoustic wave
(acoustic sound), to detect mechanical shocks and/or to detect structure-borne sound.
For example, the lighting device can be mounted on or near a door and the sensor can
detect vibrations (mechanical shocks) caused by opening or closing the door. The component
is connected to the housing in such a way that the housing and the component react
differently in their movements to the vibrations (pressure/acoustic wave, mechanical
shocks) acting on the lighting device. This difference is detected by the sensor.
[0010] The signals generated by the sensor can be used for lighting control and/or non-lighting
application such as detecting imbalance in a rotating machine, counting passing vehicles,
determining the type of vehicle, detecting earthquakes, exposures or a shot from a
gun and/or voice control of household appliances.
[0011] The lighting device can comprise an interface configured to output, via cable or
radio, signals or information generated by the sensor to another device and/or can
comprise a control means configured to control the lighting device based on the signals
or information.
[0012] The control means can be configured to generate a control or warn signal based on
the vibrations detected by the at least one sensor. Preferably, the control means
is configured to detect at least one of a predetermined vibration intensity, a predetermined
vibration pattern, a predetermined voice and a predetermined voice command and is
configured to generate the control or warn signal when the predetermined vibration
intensity, the predetermined vibration pattern, the predetermined voice and/or the
predetermined voice command is detected.
[0013] The control or warn signal can be output to the other device instead of or in addition
to the sensor signals. In addition or alternatively, the lighting device can comprise
a light source controlled by the control means. In addition, the light source can
be controlled and powered by an electronic control gear comprising the control means.
The control means may contain one or more microcontroller circuits or application
specific integrated circuits (ASICs).
[0014] The at least one component can be a circuit board having a ground plane or power
plane isolated from the housing and/or isolated from a metal plate connected to the
housing. The ground/power plane and the (metallic) housing/metal plate form a parallel-plate
capacitor, in which a distance between its plates is affected by the vibrations and
the change in capacitance caused by the vibrations is detected by the sensor by, for
example, detecting voltage between the ground/power plane and the housing/metal plate.
The circuit board can be a component of a LED module or the electronic control gear.
[0015] In addition or alternatively, the at least one component can be a translucent plate
that transmits light generated by the lighting device and prevents the ingress of
dust and humidity, wherein the at least one sensor is configured to detect light reflected/diverted
by the translucent plate. The light reflected/diverted by the translucent plate can
be ambient light or emitted from a light source of the lighting device. In addition,
the translucent plate can comprise a reflector for reflecting, to the at least one
sensor, the light emitted by the light source.
[0016] The component can be a thin foil to easily detect acoustic sound/speech, wherein
the foil closes an opening of the housing and the at least one sensor detects light
reflected/diverted by the foil. The light reflected/diverted by the foil can be ambient
light or emitted from the light source of the lighting device. Preferably, the housing
can comprise a translucent cover, wherein the foil closes an opening in the translucent
cover.
[0017] In addition or alternatively, the housing can comprise an opening for pressure equalization.
[0018] A signal generated by the at least one sensor can be output to another lighting device
and/or an external control device.
[0019] According to the present invention, a system comprises a plurality of the lighting
devices and the control device configured to receive the sensor signals and to control
the plurality of the lighting devices based on the received sensor signals.
[0020] At least some of the plurality of the lighting devices can be located in different
locations, wherein the control device is configured to determine a point of origin
of the vibrations and/or a change of the point of origin based on the received sensor
signals and is configured to control the plurality of the lighting devices based on
the detected point of origin and/or the detected change.
[0021] According to the present invention, a method for detecting vibrations in an environment
of a lighting device comprises a detecting step for detecting a movement of at least
one component of the lighting device relative to the housing of the lighting device
caused by the vibrations.
[0022] The lighting device can be a downlight luminaire, a luminaire for indoor use (freestanding
luminaire, wall-mounted luminaire) or an outdoor luminaire for illuminating streets,
roads, paths, buildings, facades or walls.
[0023] Embodiments of the invention are discussed in detail with reference to the enclosed
figures, in which
FIG. 1 shows a schematic view of parts of a lighting device according to a first embodiment
of the present invention,
FIG. 2 shows a schematic view of parts of a lighting device according to a second
embodiment of the present invention,
FIG. 3 shows a schematic view of parts of a lighting device according to a third embodiment
of the present invention and
FIG. 4 shows a flowchart of the method according to an embodiment of the present invention.
[0024] In the figures, same reference numbers denote same or equivalent structures. The
explanation of structures with same reference numbers in different figures is avoided
where deemed possible for sake of conciseness.
[0025] FIG. 1 shows a lighting device 1 according to a first embodiment of the present invention
in a sectional view. The lighting device 1 is mounted on a ceiling 2 and comprises
a light source 3, an electronic control gear/ballast 4 for the light source 2 and
a housing 5, in which the light source 3 and the electronic control gear 4 are disposed.
The housing 5 comprises a translucent enclosure part 6 (e.g. transparent cover) through
which the light emitted by the light source 3 shines. The light source 3 consists
of a plurality of LEDs 7 mounted on a circuit board, wherein the LEDs 7 are connected
to the ground and power plane of the circuit board. The circuit board is attached
to the housing 5 with a double-sided adhesive pad 8, which is elastic and may have
good thermal conductivity to dissipate some of the heat generated by the light source
3 to the metal housing 5.
[0026] The lighting device 1 is configured to detect vibrations indicating, for example,
the presence of a person, and to switch on the light for a specified time when such
vibrations are detected. The vibrations of the ceiling indicated by the arrow Fi are
transmitted to the housing 5 of the lighting device 1, wherein the double-sided adhesive
pad 8 dampens the transmission of the vibrations to the circuit board (the light source
3). According to the present invention, the circuit board and the metallic housing
5 form a capacitor, in which a distance between its plates is affected by the vibrations
and the change in capacitance caused by the vibrations is detected by the electronic
control gear 4. If the housing 1 is not made of metal, a metallic plate (e.g., heat
sink) can be attached to the circuit board with the double-sided adhesive pad 8 so
that the metallic plate and the circuit board form the capacitor, wherein the metallic
plate or the circuit board is mounted on the housing 5.
[0027] The electronic control gear 4 is connected to the metallic housing 5 and the circuit
board (the light source 3) by a cable 9 and two cables 10, respectively, and determines
the change in capacitance by continuously measuring the voltage between the metallic
housing 5 and the ground or power plane of the circuit board, wherein the light is
switched on when the voltage or a value derived from it (e.g., by filtering) is greater
than or equal to a threshold. Alternatively, the electronic control gear 4 can determine
the change in capacitance by determining a change in the resonant frequency of a resonant
circuit that includes the capacitor formed by the circuit board and the metallic housing
5, wherein the light is switched on when the change is greater than or equal to a
threshold.
[0028] Depending on the design of the lighting device 1, vibrations can reduce the service
life of the lighting device 1 or the light source 3. In addition or as an alternative
to presence detection, the strength and/or duration of the vibrations can be determined
continuously for service life calculation or maintenance planning. The electronic
control gear 4 or other internal or external control device can perform the service
life calculation and/or the maintenance planning.
[0029] The lighting device 1 shown in FIG. 2 comprises a sensor 12 configured to also detect
vibrations that propagate as acoustic waves and act on the transparent cover 6a of
the lighting device 1. The transparent cover 6a is connected to the housing 5 by elastic
elements 11 so that it can move in the direction of the arrow F2 when the acoustic
waves (e.g., loud sounds) act on the transparent cover 6a and the housing 5 can move
relative to the transparent cover 6a when vibrations of the ceiling are transmitted
to the housing 5. Alternatively or in addition, the transparent cover 6a may be made
of an elastic material.
[0030] A reflector 13 is mounted on the transparent cover 6a to reflect light emitted by
the light source 3 to the sensor 12, wherein the light reflected to the sensor 12
depends on the movement/deflection of the transparent cover 6a caused by the vibrations.
The sensor 12 detects the reflected light and transmits a sensor signal to the electronic
control gear 4 via cables 14. The electronic control gear 4 estimates the vibrations
based on the sensor signal and controls the light source 3 based on the estimation.
In this way, the electronic control gear 4 can extend the switch-on time by a certain
duration when vibrations indicating the presence of a person are detected, wherein
a predetermined vibration intensity and/or a predetermined vibration pattern is assigned
to the presence. In addition or as an alternative to presence detection, vibrations
indicating a dangerous situation can be detected, a warn signal can be transmitted
to an output device via cable or radio.
[0031] The lighting device 1 shown in FIG. 3 is configured to detect low intensity acoustic
waves/sound, such as speech. The transparent cover 6b of the lighting device 1 shown
in FIG. 3 has an opening 15, which is hermetically closed with a foil/film 16. Similar
to the reflector 14 shown in FIG. 2, the foil 16 reflects the light emitted by the
light source 3 to the sensor 12 and vibrates when the acoustic waves act on the foil
16. Since the foil 16 is lighter and more elastic than the transparent cover 6a, the
sensitivity is increased. In order to protect the foil 16, the housing 5 has an opening
17 for pressure equalization.
[0032] In the embodiments shown in FIG. 2 and FIG. 3, light emitted by the light source
3 is reflected to the sensor 12 to reduce the number of components required to provide
the sensor function. Alternatively, a separate light source such as a laser or infrared
LED can be used to allow detection even when the light source 3 is switched off.
[0033] FIG. 4 shows a very simplistic flowchart showing the single steps performed by the
method described in detail above. In step Si, movements of one or more components
relative to the housing are detected. In step S2, presence of vibrations, type of
vibrations (voice, explosion, shock ...) and/or the information contained in the vibrations
(voice information) is determined and a signal assigned to the determined event, type
or information is output.
1. Lighting device, comprising
a housing (5),
at least one component (3, 6a, 16) elastically connected to the housing (5), and
at least one sensor (4, 12) configured to detect vibrations in an environment of the
lighting device (1) by detecting a movement of the at least one component (3, 6a,
16) relative to the housing (5) caused by the vibrations.
2. The lighting device according to claim 1, further comprising
a control means (4) configured to generate a control or warn signal based on the vibrations
detected by the at least one sensor (4, 12), wherein
the control means (4) is configured to detect at least one of a predetermined vibration
intensity, a predetermined vibration pattern, a predetermined voice and a predetermined
voice command and is configured to generate the control or warn signal when the predetermined
vibration intensity, the predetermined vibration pattern, the predetermined voice
and/or the predetermined voice command is detected.
3. The lighting device according to claim 2, further comprising
a light source (3) controlled by the control means (4).
4. The lighting device according to claim 3, wherein
the light source (3) is controlled and powered by an electronic control gear comprising
the control means (4).
5. The lighting device according to any one of the preceding claims, wherein
the at least one component (3, 6a, 16) is a circuit board having a ground plane or
power plane isolated from the housing (5) and/or isolated from a metal plate connected
to the housing (5), and
the at least one sensor (6) is configured to detect capacitance between the ground
plane or power plane and the housing (5) or metal plate.
6. The lighting device according to claim 5, wherein
the circuit board is a component of a LED module.
7. The lighting device according to any one of the preceding claims, wherein
the at least one component (3, 6a, 16) is a translucent plate (6a), and
the at least one sensor (6) is configured to detect light reflected/diverted by the
translucent plate (6a).
8. The lighting device according to claim 7, wherein
the translucent plate (6a) comprises a reflector (13) for reflecting, to the at least
one sensor (4, 12), light emitted by a light source (3) of the lighting device (1).
9. The lighting device according to any one of the preceding claims, wherein
the at least one component is a foil (16), which closes an opening of the housing
(5), and
the at least one sensor (4, 12) is configured to detect light reflected/diverted by
the foil (16).
10. The lighting device according to claim 9, wherein
the housing (5) comprises a translucent cover (6b), and
the foil (16) closes an opening in the translucent cover (6b).
11. The lighting device according to any one of the preceding claims, wherein
the housing (5) comprises an opening (17) for pressure equalization.
12. The lighting device according to any one of the preceding claims, further comprising
output means for outputting a sensor signal generated by the at least one sensor (4,12).
13. System comprising
a plurality of the lighting devices (1) according to claim 12, and
a control device configured to receive the sensor signals and to control the plurality
of the lighting devices (1) based on the received sensor signals.
14. The lighting device according to claim 13, wherein
at least some of the plurality of the lighting devices (1) are located in different
locations, and
the control device is configured to determine a point of origin of the vibrations
and/or a change of the point of origin based on the received sensor signals and is
configured to control the plurality of the lighting devices (1) based on the detected
point of origin and/or the detected change.
15. Method for detecting vibrations in an environment of a lighting device comprising
a housing and at least one component elastically connected to the housing, wherein
the method comprises the step of:
detecting a movement of the at least one component relative to the housing caused
by the vibrations.