The present invention refers to lamp sockets with a new structure and function. In particular is referred to such lamp sockets that normally constitute a part of so called low energy lamps containing ignition and drive circuits for a related discharge lamp and intended to be screwed into common sockets.

A problem that is solved by the present invention, is in a siπtple way to control illumination according to various needs without making any expensive and unflexible stationary installation. By means of the invention normal light fittings can be used for lighting that will be automatically controllable depending on surrounding light or depending on time. It may also be controlled to be turned on, turned off or varied by means of remote control. According to the invention this problem is solved by building in a light sensitive sensor and electronics into the lamp socket or in connection thereto for the functions that are required for the control.

By building in electronics for various functions in direct connection to the lamp socket of a low energy lamp or an adapter provided with a lamp socket for a lamp of low energy type and only use one or several sensors which are sensitive to light or other electromagnetic radiation, various functions may be controlled and various embodiments realized without the socket or adapter needs to be provided with mechanical or electro mechanical keys or other setting devices. A closed housing which lets through light or signals of other wavelengths to the sensor can be used, whereby the socket or adapter can meet the requirements of electric safety also for outdoors use.

Various functions may be controlled by the sensor. In one embodiment the sensor is arranged to detect the surrounding light and forward supply voltage to the lamp when the light is below a certain level. This function may be combined with

a timer ciruit which disconnects the supply voltage a predetermined time after the light first was below the level.

In a particularly preferred embodiment the device is also provided with a built in twenty-four hour timer that is automatically set according to the day and night rythm after the device has been connected. In this the sensor is used to detect dusk and dawn or sunset and sunrise and the sensor is arranged to adjust the twenty-four hour timer to correct sun time after detection of at least one sunset and one sunrise. With this embodiment the lamp socket according to the invention may be arranged to for example switch on the light at sunset and switch off at a certain time of the day and night, controlled by the adjusted sun timer. Other switching functions are also possible with other programming. In an embodiment according to the present invention a sensor in the lamp socket or adapter in addition is arranged to sense and receive signals from a remote control and the supply voltage to the lamp or other functions are arranged to be controlled by the signals.

An object of the present invention is thus to provide compactly built switching devices in lamp sockets and adapters for lamps. An object is also to be able to actively control these switching devices by a light sensor or other electromagnetic radiaton sensor so that mechanical or other setting means are not required to obtain a desired function. Programmed electronic functions make a compact structure possible. These and other objects are met with by giving the device according to the invention a structure and functions according to what is stated in greater detail in the subsequent patent claims.

Through GB A 2 213 983 a lamp with a built in sensor is previously known. This is however only intended to sense states of the environment such as environmental light or movement detection, not active control signals from a transmitter.

The invention will now be described in closer detail with reference to subsequent drawings.

Figure 1 shows an example of the external structure of a device according to the invention.

Figure 2 shows diagrammatically an example of a block diagram of a device according to the invention.

Figure 3 shows an example of an algorithm which can be used in a program for calculation when dusk and dawn occurs.

A lamp socket or adapter 1 according to one embodiment of the invention as for the external appearance is designed similar to the sockets that are common at low energy lamps intended to replace light bulbs in common bulb sockets. The lamp socket 1 thus constitutes an enlargement of a common bulb socket 2 in order to contain the ignition and drive circuits that are required for operation of a discharge tube 4 which is permanently or exchangeably mounted in the socket 1 and which can be surrounded by a protection envelope 3. The socket 1 may contain a window 5, inside which a sensor for visible light or other electromagnetic radiation is provided, but the socket 1 can also be made of a material that in itself is permeable enough for the frequencies in question that the sensor shall detect. The socket 1 also contains the additional electronic circuits which according to the invention are required for control of the operating voltage for the tube 4.

Figure 2 shows the structure diagrammatically of a switching device in the socket 1. Between the bulb socket 2 and the conventional start and drive electronics 6 for the bulb or the discharge tube 4 a switch 10 is provided so that the supply voltage to the lamp 4 and its start and drive electronics can be controlled. A control device 9 controls the on and off state according to predetermined conditions. The control device can be built up from conventional micro

electronics and may have the functions that are stated in closer detail below. In addition to these circuits there is provided a sensor 8 for light or other electromagnetic radiation and a DC-supply 7 for current supply of the circuits.

The control device 9 is preferably built up from a microprocessor which has been programmed for the functions that are desired for the various versions of the invention. No movable parts or setting devices are required for control of the switching device but this is controlled by software stored in the control device and by signals from the sensor 8.

An example of an algorithm that can be used in a program for calculation when dusk and dawn occurs is shown in Figure 3. This can be used for example in a one chip computer of the type 68HC05, which may constitute the main component of the control device 9. It appears from the flow chart that a light counter counts through a number of steps of six seconds up to 255 or down to zero before dark or light has been determined, whereby a filter against error detection is obtained. This algorithm is incorporated as a part of the program in the control device that controls the switch 10.

In its simplest embodiment the switching device can be designed to keep the lamp connected to the operating during a predetermined fixed time before or after the switching device has been connected and that this period is repeated on a twenty-four hour basis.

An especially favourable embodiment of the present invention is obtained when the sensor provided to the control device is adapted for detection of daylight and the switching device is arranged to sense when the daylight ceases and returns. The sensor may be constituted by a photo sensitive detector placed on a circuit board in the socket 1 whereby the socket kan be made of a plastic material with permeability for suitable frequencies of the daylight or the sensor can also

be located at the window 5. One or several light guides alteratively may be provided from the sensor to the outside of the socket 1. Most plastic materials let through light enough for daylight detection. The sensor is connected in a known manner to a threshold detector which is incorporated in the control device 9. In order to distinguish the variations of the daylight from other light changes the threshold value circuit or other circuits or programs in the control device are arranged only to react on the slow changes that the daylight exhibits and filter off more rapid courses, which can be carried out by the algorithm according to Figure 3.

In an embodiment of the switching device the control device 9 is arranged to actuate the switch 10 into on-position when the daylight ceases and again disconnect at the time of the day when the switching device has been connected. This function can be obtained by appropriate programming by a twenty-four hour timer included in the control device that starts as the switching device is connected.

In a further embodiment of the switching device a twenty-four hour timer circuit in the control device is adjusted according to the daylight so' that the twenty-four hour timer mainly is synchronized with the time of the day independently of what time of where or what time of the day or year the switching device is connected. The timer circuit in the control device is adjusted by it being automatically set at midnight between the times when the daylight ceases and returns whereby it is synchronized with the sun time at the location where it is used. The control device 9 may be designed such that it actuates the switch 10 when the daylight ceases and actuates it again when the adjusted timer circuit indicates a predetermined time of the day. Before the timer circuit is adjusted, that is during the first day and night that the device is connected, switching off may occur after a fixed programmed time. By this embodiment it is possible to connect the device at any time of the day and night and without manual time setting obtain a correct adjustment of the internal clock after a setting period. This

automatic time adjustment function is particularly functional in those cases when the switching device is connected such that the current supply easily may be interrupted for example by the operation of a switch, whereafter no manual adjustment of the built in timer is required.

In a preferred embodiment of the invention a sensor and the control device designed such that the functions of the device may be controlled by a remote control device. Hereby the on and off function of the switch but also for example the intensity of light may be controlled by the remote control. This function may be combined with one or several of the above indicated functions, whereby one or several sensors for the various functions may be connected to the control device. In an especially preferable design the control device is programmed to be able to be readjusted according to various types of remote controls so that it "recognizes" and is only actuated by a certain signal from a specified remote control after this has first been initiated.

In still another embodiment of the switching device according to the invention it is also provided with means for a random connection and disconnection of the circuit to the lamp. This design may be combined to the rest of the functions according to the above so that the random connection and disconnection only occurs when the circuit otherwise should be connected.