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The invention refers to a luminaire, comprising a sensor device with an antenna for wireless communication, for improving the overall radiation characteristic of the luminaire.
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Nowadays, luminaires are packed with a plurality of functional features which go beyond the illumination of an area. Especially, when luminaires are incorporated into more intelligent control systems, the luminaires must provide means for the intelligent control. However, even single luminaires tend to provide functionality that is more sophisticated.
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A major aspect in intelligent luminaire system is provided by the usage of sensor devices within the luminaire. For instance, luminaires are enabled to recognize the presence of objects or persons via PIR-sensor devices. In addition, the sensor devices comprise antennas for wireless communication when e.g. using wireless control systems like Matter or ZigBee.
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Due to the design requirements of the luminaires, the sensor devices are commonly desired to be arranged within the luminaire housing, such that an aesthetic design is achieved. However, this design bears risks with regard to the performance of the antenna for wireless communication. That is, radiation characteristics of the antenna highly depend on the entire construction of the luminaire. Therefore, the housing may negatively affect the radiation characteristic of the single antenna. Furthermore, the supporting means for carrying the luminaires may also negatively affect the radiation characteristic of the single antenna, as e.g. it is the case for ceiling luminaires in general.
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In the scope of the application, the terms "radiation characteristic" and "radiation pattern" are considered to have equivalent meaning.
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In consequence, the communication to other communication participants may be negatively affected by the overall luminaire design.
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Solutions for improving the radiation characteristic are known for luminaires that comprise means for wireless communication as shown in
DE 10 2022 119 696 A1 and
WO 2021/069473 . Therefore, openings in form of slot antennas or openings for adjusting the impedance at the opening to the characteristic impedance are disclosed to be formed in the luminaire housing. This solutions mainly focus on providing a path for the electromagnetic waves to travel in which the damping is less than it would be otherwise when traveling through the luminaire housing.
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Furthermore, solutions for luminaires with special requirements like pendant luminaires may also provide slot antennas for improving the radiation characteristic of the antenna as disclosed in
EP4357665 A1 .
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EP 4 322 335 A1 disclose a slot antenna within an installation housing for installation in a building structure or a building technology device.
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However, the prior art does not disclose a solution for improvement of the overall radiation characteristic of a luminaire comprising an antenna in a sensor device that is part of the luminaire. In particular, the sensor device comprises a sensing module that itself comprises a sensitive area, and in order to allow the sensitive area to receive radiation, a corresponding opening within the housing must exist already. However, the corresponding opening may allow to establish a communication via the antenna comprised in the sensor device, yet the communication characteristics are rather bad due to the overall radiation characteristics of the luminaire.
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In order to overcome the above mentioned objective technical problems, this application provides a luminaire according to the enclosed independent claims. The invention is defined in the appended claims. Advantageous features of the present invention are defined in the corresponding dependent claims.
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For the scope of the invention, when talking about radiation, it is also meant the reception due to the reciprocity of antennas, when excluding internal elements like amplifiers.
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A luminaire, comprises a sensor device that comprises a sensing module and an antenna for wireless communication; and a light emitting area for emitting light into a light emission direction. The sensor device is located laterally to the light emitting area in the light emission direction. A first opening is arranged in a surface that is facing a detection area of the sensing module, and the first opening is arranged such that the light incident to the first opening hits a light-sensitive area of the sensing. In addition to the first opening, a slot antenna is arranged in a metallized or metallic surface that is facing the detection area of the sensing module; and the slot antenna is electromagnetically coupled to the antenna.
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The light emitting area is an area that is defined by any area that is emitting light rays, which illuminate the environment of the luminaire. In particular, it is referred to the light rays that follow a direct path towards the area that shall be illuminated, meaning any undesired reflections within the luminaire such that an undesired area is crossed by the light rays is neglected.
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The light emission direction is the main direction in which the light is emitted. Basically, it is often understood to be the direction from the light source to the center of the desired illumination area.
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The detection area of the sensing module is understood to be the area for which the sensor device and in particular the sensing module is able to capture information. Accordingly, the direction of the detection area is the main direction of the detection area.
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The luminaire may be any device that generates light, generally by conversion of electrical energy. The luminaire may comprise means for a DALI allowing the luminaire to be integrated within a DALI network and to use the control and communication functionality of a DALI network. Moreover, the luminaire may comprise means for alternative control and/or communication protocols. Standardized wired protocols may be, yet not being limited to 0-10V DC, DMX, RDM, BACnet, LonWorks, KNX, X10, HomePlug or G.hn. Standardized wireless protocols may be but are not limited to ZigBee, 6LoWPAN, Z-Wave or EnOcean. In particular, the luminaire further comprises means for being connected to standard mains networks. Moreover, the luminaire comprises means, like a power supply unit, allowing the luminaire to be operated when the connection to the mains network is interrupted or disconnected. Hence, an internal stand-alone power supply unit, like a battery or a rechargeable battery may be comprised in the luminaire for operating the luminaire when the connection to the mains network is interrupted or disconnected. Furthermore, the luminaire may comprise common means for a luminaire, in particular means with respect to the, housing, mounting, light source, circuit safety mechanisms or the circuit itself.
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The sensor device may be any device for sensing and wireless communication like a motion/occupancy sensor, light sensor, temperature sensor or the like.
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Therefore, the sensing module could be a PIR-sensor, microwave sensor, ultrasonic sensor or the like.
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The antenna for wireless communication could be any antenna for wireless communication like a patch antenna, a monopole antenna, a dipole antenna, an angled monopole antenna or the like.
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The sensitive area of the sensing module may be the sensitive area of a pyroelectric sensor in case of PIR-sensors or the like in case of different sensors.
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Preferably, the slot antenna has the length of half of the wavelength of the radiated or received signal or an integer multiple thereof. Preferably, a path that ranges from one end of the slot antenna to another and that is located in the middle between the upper and lower edge of the antenna has the length of half of the wavelength of the radiated or received signal or an integer multiple thereof.
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Metallic materials are understood to be materials that are inherently composed of metal or metal alloys, whereas metallized materials are understood to be coated or treated with a thin layer of metal.
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An advantageous effect of the foregoing embodiment is that the luminaire provides an improved radiation characteristic of the overall luminaire. This is, in addition to the opening for the sensing module, a slot antenna is provided which due to its resonant characteristic improves the radiation characteristic of the antenna, e.g. by improving the out coupling efficiency or the overall radiation power.
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In an embodiment of the luminaire, the slot antenna overlaps the antenna when projected onto the surface.
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Preferably, the slot antenna at least completely overlaps the antenna when projected onto the surface.
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An advantageous effect of the foregoing embodiment is that the radiation characteristic of the overall luminaire can be improved. That is, when the slot antenna overlaps the antenna when projected onto the surface, the slot antenna is fed by a rather high field.
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In an embodiment, the center points of the projections of the antenna and the slot antenna are aligned.
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In the scope of the invention, under projection it is referred to orthogonal projection.
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An advantageous effect of the foregoing embodiment is that the radiation characteristic of the overall luminaire can be improved. That is, when the center points of the projections of the antenna and the slot antenna are aligned, the slot antenna is fed by a rather high field.
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In an embodiment of the luminaire, the slot antenna is formed point-symmetrical with respect to the center point.
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An advantageous effect of the foregoing embodiment is that the overall radiation characteristic is formed more symmetrically with respect to the center point. Often, the antenna has been designed to provide symmetrical radiation characteristics, which are deformed by the surrounding luminaire structure, such that the symmetry can be improved by the foregoing embodiment.
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In an embodiment of the luminaire, the antenna shows an axial arrangement, and the slot antenna comprises a first straight portion that is obliquely arranged to the axial arrangement when pro-j ected on the surface.
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An advantageous effect of the foregoing embodiment is that the overall radiation characteristic may be changed due to beam shaping by an obliquely arranged slot antenna. Thus, different results can be achieved when compared to a slot antenna that is arranged in parallel or perpendicular to the projection of the axial arrangement of the antenna on the surface. In particular, some antennas like the angled monopole antenna tend to form minima of the radiation characteristic of the corresponding antenna in direction of one of the main axis of the corresponding antenna. By the oblique arrangement, the antenna pattern can be shifted. Preferably, the antenna pattern is shifted such that the minima of the radiation pattern do not align with one of the main axis of the corresponding antenna. Furthermore, a rather space saving arrangement of a slot antenna is achieved.
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In an embodiment of the luminaire, the slot antenna comprises a second and third straight portion that extend from the ends of the first straight portion in a direction perpendicular to the axial arrangement.
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An advantageous effect of the foregoing embodiment is that a width and height can be reduced for a slot antenna.
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In an embodiment of the luminaire, the antenna is an angled monopole antenna.
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An advantageous effect of the foregoing embodiment is that the required space can be reduced.
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In an embodiment of the luminaire, a housing for carrying the sensor device is comprised, wherein the surface and the metallized or metallic surface are part of the housing for carrying the sensor device.
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Preferably, the housing cuboid-shaped.
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Alternatively or additionally, the housing has rounded corners.
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Alternatively or additionally, the housing is comprised of a plurality of joined surfaces.
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Alternatively or additionally, the housing is integrally formed.
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An advantageous effect of the foregoing embodiment is that the sensor device may be protected by the housing, and the overall radiation characteristics of the luminaire are improved.
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In an embodiment of the luminaire, apart from the metallized or metallic surface, the housing for carrying the sensor device is made of a non-metallic and non-metallized material, or the housing for carrying the sensor device is made of metal.
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An advantageous effect of the foregoing embodiment is that the housing may be made of a material that is suited for the requirements of the luminaire.
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In an embodiment of the luminaire, the housing for carrying the sensor device provides a plurality of flat surfaces. The surfaces and the metallized or metallic surfaces are arranged in a same flat surface. An additional slot antenna is arranged in at least one of the flat surfaces different to the flat surface at which the surface and the metallized or metallic surface are arranged.
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Additionally, additional slot antennas are arranged in a plurality of flat surfaces.
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An advantageous effect of the foregoing embodiment is that an overall radiation characteristic of the luminaire may be improved.
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In an embodiment of the luminaire, the flat surface, in which the additional slot antenna is arranged, is facing a direction that aligns with a main axis of the antenna for which the radiated power is the smallest.
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By power, it is referred to any indicator that allows conclusion on the field energy. Thus, reference to the power density would be equivalent. Power is given in watts.
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An advantageous effect of the foregoing embodiment is that a radiation characteristic of the luminaire can be improved for a direction that has the smallest radiated power.
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In an embodiment of the luminaire, the housing for carrying the sensor device is a luminaire housing.
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An advantageous effect of the foregoing embodiment is that no additional housing is required.
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In an embodiment of the luminaire, a luminaire housing is comprised and a second opening is arranged in the luminaire housing at a side facing the detection area of the sensing module. The housing for carrying the sensor device is arranged within the second opening.
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An advantageous effect of the foregoing embodiment is that an additional customized housing for the sensor device is used for improving the overall radiation characteristic of the luminaire.
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In an embodiment of the luminaire, the luminaire housing is formed by a non-metallic and non-metallized material.
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An advantageous effect of the foregoing embodiment is that the negative affection of the overall radiation characteristic of the luminaire through the housing of the luminaire may be reduced.
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In the following, preferred embodiments of the present application shall be described in more detail based on the corresponding figures.
- Figure 1 is a schematic view from below a ceiling luminaire, when the ceiling luminaire is mounted on the ceiling according to an embodiment.
- Figure 2 is a schematic left view of Figure 1 according to an embodiment.
- Figure 3 is a schematic bottom view of Figure 1 according to an embodiment.
- Figure 4 is a schematic view from below a ceiling luminaire, when the ceiling luminaire is mounted on the ceiling according to an embodiment.
- Figure 5 is a schematic view from below a ceiling luminaire, when the ceiling luminaire is mounted on the ceiling according to an embodiment.
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Figure 1 is a schematic view from below a ceiling luminaire 1, when the ceiling luminaire 1 is mounted on the ceiling according to an embodiment. The luminaire 1 comprises a sensor device 11, a light emitting area 12, a first opening 13 arranged in a surface, a slot antenna arranged in a metallized or metallic surface. Internally, each module may be electrically connected to any of the other modules, which is not shown explicitly. The connection may be realized by an internal data exchange link. The internal data exchange link may be any one of Inter-Integrated Circuit (I2C), Serial Peripheral Interface (SPI), Universal Asynchronous Receiver/Transmitter (UART), Controller Area Network (CAN), Universal Serial Bus (USB), General Purpose Input/Output (GPIO), Peripheral Component Interconnect Express (PCIe) or Ethernet. Further components that are comprised in a common luminaire may be comprised by luminaire 1, which is not shown here explicitly.
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The sensor device 11 comprises a sensing module 111 and an antenna 112 for wireless communication.
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The sensor device 11 comprises a main body in cuboid-shape with rounded corners.
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The sensing module 111 is arranged at a surface of the main body that is facing the light emission direction of the luminaire 1.
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The sensing module 111 is in cuboid shape.
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The antenna 112 is arranged at the same surface of the main body as the sensing module 111.
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The cover of the antenna 112 is in cuboid-shape.
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Alternatively or additionally, the antenna 112 is an angled monopole antenna.
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Alternatively or additionally, the sensing module 111 is a pyroelectric sensor for motion/occupancy detection.
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The wireless communication may be any wireless communication that allows transmission of information within the transmitted signal. Information may be transmitted via a signal by common modulation techniques, in particular by Pulse Position Modulation (PPM), Pulse Amplitude Modulation (PAM), Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), Frequency Shift Keying (FSK). For reasons of efficiency, the signal may be encoded by common encoding techniques, in particular by Linear Block Codes, Convolutional Codes, Turbo Codes, Low Density Parity Check Codes, LT and Raptor Codes, Polar Codes or Space-Time Coding.
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The luminaire 1 may comprise means for a DALI allowing to the luminaire to be integrated within a DALI network and to use the control and communication functionality of a DALI network. Moreover, the luminaire 1 may comprise means for alternative control and/or communication protocols. Standardized wired protocols may be, yet not being limited to 0-10V DC, DMX, RDM, BACnet, LonWorks, KNX, X10, HomePlug or G.hn. Standardized wireless protocols may be but are not limited to ZigBee, 6LoWPAN, Z-Wave or EnOcean. In particular, the luminaire 1 further comprises means for being connected to standard mains networks. Moreover, the luminaire 1 comprises means, like a power supply unit, allowing the luminaire to be operated when the connection to the mains network is interrupted or disconnected. Hence, an internal stand-alone power supply unit, like a battery or a rechargeable battery may be comprised in the luminaire 1 for operating the luminaire 1 when the connection to the mains network is interrupted or disconnected. Furthermore, the luminaire 1 may comprise common means for a luminaire, in particular means with respect to the, housing, mounting, light source, circuit safety mechanisms or the circuit itself.
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The light emitting area 12 comprises a light source. In Figure 1, the light source is an LED tube. Furthermore, in Figure 1 the light emitting area 12 comprises a transparent cover to protect the light source. However, the light emitting area 12 must at least comprise a light source.
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The opening 13 is formed as an opening in a surface facing the detection area of the sensing module 111 that is a surface of a luminaire housing 15. The opening 13 overlaps the sensing module 111 in the view of Figure 1.
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The slot antenna 141 is formed as an opening in the surface facing the detection area of the sensing module 111 that is the surface of the luminaire housing 15. The slot antenna 141 overlaps the antenna in the view of Figure 1. The center points of the projections of the antenna 112 and the slot antenna 141 onto the surface of the luminaire housing 15 that is facing the detection area of the sensing module 111 are aligned. The slot antenna 141 is formed point-symmetrically with respect to the center point.
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The projection of the antenna 112 onto the surface of the luminaire housing 15 at which the opening 13 and the slot antenna 141 are arranged, shows an axial arrangement. In particular, the projection shows that the antenna 112 extends in axial direction that is parallel to the upper and lower edge of the luminaire housing 15.
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The slot antenna 141 is formed to be rectangular-shaped. The slot antenna 141 is obliquely arranged to the axial arrangement of the projection of antenna 112.
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By this configuration, the slot antenna 141 may be formed such that it extends past the opening 13. Furthermore, the required height and width within the luminaire housing 15 can be reduced.
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This is not trivial, as it should be considered that for a communication with e.g. 2.4 GHz, the minimum length of the slot antenna 141 is about 6cm, which generally is in the range of the length of the entire sensor device 11. Hence, the arrangement of the slot antenna 141 and the opening 13 is generally a major challenge.
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Furthermore, the antenna 112, which is an angled monopole antenna, tends to form minimum of the radiation characteristic of the corresponding antenna in direction of one of the main axis of the corresponding antenna. By the oblique arrangement, the antenna pattern can be shifted. Preferably, the antenna pattern is shifted such that the minima of the radiation pattern do not align with one of the main axis of the corresponding antenna. In particular, this may be achieved for any oblique arrangement at any of the side surfaces of the luminaire luminaire housing 15.
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The antenna 112 is electromagnetically coupled to the slot antenna 141.
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It should be noted that a general opening cannot be considered to function as a slot antenna 141 as an antenna is generally a resonant structure for out coupling electromagnetic waves into free space.
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The luminaire housing 15 may be a metallic or a metallized luminaire housing.
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Alternatively or additionally, the luminaire housing 15 comprises a surface in which the slot antenna 141 is arranged that is a metallic or a metallized surface.
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Alternatively or additionally, the luminaire housing 15 may be, apart of the surface in which the slot antenna 141 is arranged, a non-metallic or non-metallized surface.
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Alternatively or additionally, each subsurface of the luminaire housing 15 may be integrally formed or may be joined by separate parts.
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Figure 2 is a schematic left view of Figure 1 according to an embodiment.
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As the luminaire 1 shown in Figure 2 corresponds to the luminaire 1 shown in Figure 1 the above mentioned features and their description is considered to be inherently adopted for the description of Figure 2 without further notice.
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Figure 2 additionally shows an additional slot antenna 142 that is formed on the left side surface of the luminaire housing 15.
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The additional slot antenna 142 may inherently adopt any of the previously described features with respect to the slot antenna 141.
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Figure 3 is a schematic bottom view of Figure 1 according to an embodiment.
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As the luminaire 1 shown in Figure 3 corresponds to the luminaire 1 shown in Figure 1 and Figure 2 the above mentioned features and their description is considered to be inherently adopted for the description of Figure 3 without further notice.
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Figure 3 additionally shows an additional slot antenna 143 that is formed on the bottom side surface of the luminaire housing 15. The bottom side surface is not to be confused with the back side surface.
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The additional slot antenna 143 may inherently adopt any of the previously described features with respect to the slot antenna 141.
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The arrow R2 represents the direction of the detection area of the sensing module 111.
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The arrow R1 represents the direction of the light emission of the luminaire 1.
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Figure 4 is a schematic view from below a ceiling luminaire 1, when the ceiling luminaire 1 is mounted on the ceiling according to an embodiment.
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As the luminaire 1 shown in Figure 4 corresponds to the luminaire 1 shown in Figure 1 to Figure 3 the above mentioned features and their description is considered to be inherently adopted for the description of Figure 4 without further notice.
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As shown in Figure 3, a housing 16 is comprised by the luminaire 1 that is not the luminaire housing 15.
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In this embodiment, the slot antenna 141 and the opening 13 are arranged in the housing 16. The housing 16 carries the sensor device 11.
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The luminaire housing 15 provides an additional opening on the surface facing the light emission direction for placing the housing 16 within the luminaire 1.
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As the housing 16 is a similarly shaped smaller housing than the luminaire housing 15, the housing 16 may inherently adopt any features of the housing 15 with respect to the arrangement of the slot antennas.
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The dimensions of the housing 16 may vary. Preferably, the dimensions of the housing are chosen to establish an improvement of the overall radiation pattern of the luminaire 1.
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The housing 16 is preferably a metallic or metallized housing.
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Preferably, the housing 16 is used in case that the luminaire housing 15 is a non-metallic or non-metallized housing.
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The shown form of the slot antenna 144 in Figure 5 may also be arranged at the housing 16.
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Figure 5 is a schematic view from below a ceiling luminaire 1, when the ceiling luminaire 1 is mounted on the ceiling according to an embodiment.
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As the luminaire 1 shown in Figure 5 corresponds to the luminaire 1 shown in Figure 1 to Figure 3 the above mentioned features and their description is considered to be inherently adopted for the description of Figure 5 without further notice.
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The slot antenna 144 differs from slot antenna 141, such that the slot antenna 144 comprises a second 144b and third 144a straight portion that extend from the ends of a first straight portion 144a in a direction perpendicular to the axial arrangement of the projection of the antenna 112.
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The dashed line within slot antenna 144 ranges from one end of the slot antenna to another and that is located in the middle between the upper and lower edge of the antenna.
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Preferably, this path has the length of half of the wavelength of the radiated or received signal or an integer multiple thereof.
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The form may also be referred to as being "Z"-shaped.
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In general, for surfaces facing a direction other than the detection area of the sensing module 111, the additional slot antenna is preferably arranged in a surface facing a direction that aligns with a main axis of the antenna for which the radiated power is the smallest.