FIELD OF THE INVENTION

The invention concerns a light housing incorporating at least one metal portion and having at least one antenna.

BACKGROUND OF THE INVENTION

Movement detectors for detecting the presence of persons are based either on infrared sensors or high-frequency (RF) sensors. Movement detectors of this kind are regularly also used in light housings, particularly in outside lighting systems. Presence detectors based on infrared sensors detect changes in heat within a defined area around the sensor itself. High-frequency sensors emit high-frequency waves via an antenna and detect the modification of a received echo of the emitted waves in a defined bandwidth. Movement detectors based on RF sensors have the advantage of not being influenced so much by changes in natural heat, for example, solar radiation or even nearby heat sources, such as electronic devices. Conventional RF detectors fitted into lights are based on an RF module which generates a high-frequency signal and receives the echo of it and is connected to an antenna. This antenna often takes the form of a simple wire or patch antenna arranged on the RF module itself. This limits the number of ways in which the RF module can be arranged, as it can be positioned only in places where the emitted signals are not impaired or obstructed by metal parts. Furthermore, the RF module or its antenna are often required to be unseen from outside, an arrangement which restricts the design of a light housing. Lastly but not least, the RF modules used and their antennas are designed to be small, so the efficiency of the antenna is very low and consequently high transmission power is necessary. This increases the radiant-flux density emitted by humans and may also lead to impairment of electronic devices. SUMMARY OF THE INVENTION

This is where the invention is intended to help. The invention is based on the problem of creating a means of transmitting and receiving for light housings which restricts the design of the housings as little as possible and also makes possible high efficiency coupled with low transmission power. According to the invention this problem is solved by making one metal portion of the light housing itself at least one antenna. The term "metal portion" is also understood to mean metal-coated portions made from non- conductive materials, such as plastics. The invention provides for a light housing with an integrated antenna which provides a means of transmitting and receiving without impairing the design of the light and which also enables high transmission efficiency coupled with low transmission power of transmission and receiving modules connected to the antenna.

In an embodiment of the invention a metal portion is formed by a reflector. The reflector may be a reflector body and a plate element to regulate the direction of radiation from a light source disposed in the light housing.

In a further development of the invention the plate element takes the form of an antenna. This enables transmitted signals to be accurately directed.

Preferably the at least one antenna is formed by at least one slot provided in the reflector body and/or the plate element. The break in the metal structure of the reflector or plate element creates a slot radiator to radiate waves. This break generally operates on the principle of the dipole, but may also have any different geometry.

Preferably the at least one slot is sealed by means of electrically non- conductive material. This enables the slot to be designed to be completely unseen. The introduction of electrically non-conductive material, such as plastic, does not impair the operation of the slot antenna formed.

Preferably the at least one slot is designed to be essentially rectangular or triangular. However, it may also have any different geometry. The design of the slot affects the direction of radiation and therefore depends on the function of the antenna at the time. In an embodiment of the invention a number of antennas which can be operated out of phase are integrated into the reflector to form an antenna array. This enables the transmitting and receiving power of the effective antenna to be increased. Depending on the application, the antenna integrated into the reflector can be connected to an RF module for the detection of persons or also to a control module to regulate the brightness and/or colour of a light. The control module can be operated by means of, for example, a remote control system. Another application is the use of the light housing as a WLAN repeater, where a corresponding repeater module is connected to the antenna. Other further developments and embodiments of the invention are set out in the remaining subclaims. An embodiment of the invention is shown in the drawing and described in detail in the following.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 : The schematic view of a reflector for a housing for fluorescent tubes;

Figure 2: The detailed view of detail II from Figure 1, and Figure 3 : The schematic view of a detail of a reflector in a further embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

The reflector 1 forming part of a housing (not shown) for a fluorescent tube and selected as an embodiment comprises two curved reflector strips 2 opposed to each other and connected to each other by plates 3. As is known, the plates 3 serve to align a fluorescent tube (not shown) disposed inside the reflector 2. In the embodiment shown the reflector is made from aluminium. Alternatively, the reflector can also be made from any other electrically conductive materials and from materials, such as plastics, coated with such materials.

In the embodiment shown in Figure 1 an essentially rectangular slot 21 is constructed in a reflector strip 2 the ends of which are not connected to one other but are bent on opposite sides. The source (not shown), for example, an RF module, is coupled to a base 22 opposite the free ends of the slot 21. The antenna is formed by the slot 21. In the embodiment shown the slot 21 is filled with plastic of a matching colour. In the embodiment shown in Figure 3 a slot 31 is constructed in a metal plate 3 to form an antenna. The slot 31 is again essentially rectangular in shape, the ends of the slot 31 being designed to be bent towards the base 32 on opposite sides. Coupling to the source is again done on the base 32 of the slot 31. It has been found that the positioning of the slot in the plate enables a high efficiency of the slot antenna thus formed to be achieved. The distinguishing feature of the present invention is that the antenna or the resonator is formed directly by a metal portion of a light, for example, the reflector of the light. The antenna integrated into the reflector has very high output power. The transmission or reception module may be positioned anywhere inside the housing. Losses of efficiency are as far as possible prevented by the metal reflector. As well as RF modules, any subassemblies which are designed for transmitting or receiving signals can be used. Thus, for example, a suitable reflector could be used in conjunction with a WLAN or DECT antenna. The design of the slot or the arrangement of slots enables the antenna output to be optimised for the respective application. Because the slots can be sealed with electrically non-conductive material they cannot be seen at all by the observer.