EP1415516A2

EP1415516A2 - Fluorescent lamp circuit

Info

Publication number: EP1415516A2
Application number: EP02747166A
Authority: EP
Inventors: Maurizio Menna
Original assignee: Innolux Optoelectronics Germany GmbH
Current assignee: Innolux Optoelectronics Germany GmbH
Priority date: 2001-05-23
Filing date: 2002-05-23
Publication date: 2004-05-06
Also published as: WO2002096163A3; WO2002096163A2; DE10125510A1; AU2002317673A1; US20040041524A1

Abstract

The invention relates to a method for operating fluorescent lamps (1, 16, 25, 36, 47, 52, 53, 74, 82), especially for increasing the service life of fluorescent lamps. The load of at least parts of at least one electrode device (2, 3, 17, 18, 32, 33, 37, 38, 48, 49, 71, 72, 75, 90) of at least one fluorescent lamp exerted by an applied electric current, especially a heating current (I), is reduced by reducing the time load and/or reducing electric power.

Description

fluorescent lamp circuit

The invention relates to a method for operating fluorescent lamps, in particular to increase the life of fluorescent lamps, the application of the method, and a fluorescent lamp circuit for operating fluorescent lamps, which is suitable for advantageously carrying out the method.

Fluorescent lamps are used today in a wide variety of designs for lighting purposes, since they are characterized by long lifetimes and high efficiency. Due to their high efficiency, fluorescent lamps only heat up to a small extent, which is advantageous for some areas of application or even a prerequisite for the use of lamps.

Fluorescent lamps are manufactured in a wide variety of shapes and sizes. Elongated, elongated, rod-shaped fluorescent lamps (the colloquially so-called "neon tubes") are still common, and are sold in different standardized lengths and ratings. Another construction is circular fluorescent lamps, in which the tube emitting light is bent into a circle. In recent years, so-called "energy-saving lamps" have also become established, i.e. fluorescent lamps, which are characterized by a particularly compact design and which have a standardized screw base for screwing into conventional light bulb holders (e.g. E14 or E27). The screw base also contains the components required to ignite and operate the fluorescent lamps. The dimensions of these so-called energy-saving lamps are chosen so that they correspond approximately to the dimensions of conventional light bulbs with a filament.

Regardless of the shape of the fluorescent lamp, the construction principle is basically the same: in a glass body there is a gas, usually mercury vapor, under very low pressure. In the gas, free electrons are accelerated in an electrical field. The accelerated electrons knock electrons out of the electron shell when they collide with a mercury atom. If the resulting mercury ion traps an electron or electrons move from an outer to an inner orbit, light energy is released. In the case of mercury, this light energy is emitted primarily in the form of UV radiation, so that the UV radiation is converted into visible light with the aid of a phosphor which is applied to the inside of the glass body of the fluorescent lamp. The electrical field required to accelerate the free electrons is generated by applying mains voltage (typically 110 V / 60 Hz or 230 V / 50 Hz AC voltage) to electrodes which are located at the two ends of the fluorescent lamp. The required number of free electrons is also brought into the gas in the fluorescent lamp via the electrodes. This requires that the electrodes are made of a material that has a relatively low work function for electrons. In addition to the applied electric field, the electrodes must have a certain temperature so that a sufficient number of electrons emerge from the electrodes.

When a fluorescent lamp is in operation, the temperature required for sufficient electron emission is maintained by heat loss at the electrodes. In order to ignite the gas discharge in the fluorescent lamp for the first time after switching on a fluorescent lamp, special techniques are required. Usually the temperature of the electrodes is increased so that a larger number of electrons can escape. For this purpose, the electrodes of the fluorescent lamp are heated electrically. The electrodes on the two sides of the fluorescent lamp are usually designed in the form of a heating coil. The two ends of the heating coil are each connected to a connection contact located on the outside of the fluorescent lamp. The electrodes of the fluorescent lamp are therefore heated by applying an electrical heating voltage to the two contacts, which are usually located at the two ends of a fluorescent lamp.

On the other hand, an increased voltage must be applied to the electrodes of the fluorescent lamp in order to start the gas discharge. This is done, for example, by a coil that is looped into the heating circuit. A so-called "quick starter" which is also in the heating current circuit suddenly interrupts the heating current flowing through the circuit and thus generates a correspondingly increased voltage at the electrodes of the fluorescent lamp through the self-induction of the coil.

Immediately after the fluorescent lamp is switched on, the electrodes located at the ends of the fluorescent lamp are first heated. After a certain period of time, the current is suddenly interrupted by the quick starter, whereby the ignition voltage required to ignite the gas discharge is applied to the two electrodes by means of the coil. During operation, there is only a low voltage between the electrodes of the fluorescent tube, since the ignited gas discharge acts practically like a short circuit.

Over time, the stresses that arise for the electrodes during the switch-on process result in one of the heating coils finally burning out. Thus, the electrodes of the fluorescent lamp can no longer be heated and the fluorescent lamp can no longer be ignited. This is a frequent reason for a defect in the fluorescent lamp. The fluorescent lamp must be replaced, although the fluorescent lamp is still functional due to the gas mixture.

This frequently occurring defect in fluorescent lamps means that the fluorescent lamp has to be replaced, which causes a corresponding outlay and corresponding costs. At the same time, there is an increased amount of hazardous waste, since the mercury usually contained in fluorescent lamps is very problematic for the environment.

Another common defect of a lamp provided with fluorescent lamps is that the quick starter has a defect. For example, the contacts of a glow lamp igniter weld more often, so that it can no longer interrupt the heating current flowing through the circuit. Firstly, the fluorescent lamp cannot therefore ignite. On the other hand, the electrodes of the fluorescent lamp are continuously supplied with a heating current, so that they are subject to greatly increased wear. This problem can only be solved by changing the quick starter. It often takes several days to recognize the defect and then replace the quick starter, during which the fluorescent lamp is subject to increased wear.

The object of the invention is to propose a method for operating fluorescent lamps and a circuit for operating fluorescent lamps, with which fluorescent lamps are operated in such a way that they have a longer life expectancy.

The object is achieved by a method according to claim 1 and a fluorescent lamp circuit according to claim 10. The object is achieved in the proposed method for operating fluorescent lamps, in particular for increasing the service life of fluorescent lamps, in that the loading of at least parts of at least one electrode device of at least one fluorescent lamp by an applied electrical current, in particular a heating current (I), is reduced by reducing the amount of time, reducing electrical power, or both. The concept of reducing the time load is not necessarily related to a single ignition process, but rather should be understood in a broad sense. For example, a method in which only a portion of the electrode devices (individual heating filaments or glow cathodes) provided in a fluorescent lamp are alternately heated, is also to be understood as a reduction in the time load, namely related to several switch-on cycles. Likewise, a method in which the number of heating cycles carried out per unit of time (for example the heating cycles per week or month) is reduced is also to be understood as a reduction in the time load, namely as a reduced time load averaged over a period of time. Of course, what has been said also applies in the event that there is a fluorescent lamp circuit with a plurality of fluorescent lamps and the load on the electrodes or electrode parts is reduced in at least some of the fluorescent lamps.

The concept of reducing electrical power is also to be understood in a broad context. In particular, this can be achieved by reducing the current strength or voltage with which the individual electrode device is acted upon. This applies particularly, but not only, to the electrical power that is applied to the electrode devices for heating them. However, a reduced electrical power can also be provided during operation of the fluorescent lamp, and the life of the fluorescent lamp can be increased in this way. The reduction in electrical power may if compensated. If the heating power is reduced, this can be done, for example, by supplying additional thermal energy, which is supplied by an additional heating device located outside the fluorescent lamp.

In any case, the load on the electrode devices of the fluorescent lamp is reduced by the proposed method and thus a longer service life of the electrode devices is achieved. Since the service life of a fluorescent lamp is normally limited by the burning of an incandescent filament, the proposed method generally also achieves a longer service life for the fluorescent lamp itself. Of course, it is also possible to achieve both a reduction in the time load and a reduction in the electrical power in combination, as a result of which a further increase in the service life of the fluorescent lamp can be achieved.

A particular advantage of the method is that it can be used together with the known, standardized fluorescent lamps, connectors, components and luminaire housings. A particularly cost-effective changeover to the proposed method is therefore possible.

An advantageous possibility of realizing the method consists in that in at least one fluorescent lamp at least on one side of the fluorescent lamp, at least parts of the electrode device located there are subjected to a heating current. Thus, during the ignition process in at least one fluorescent lamp, at most one electrode device or only parts of this electrode device is loaded by the application of a heating current, while the other electrode or both electrodes are essentially not loaded. If the electrode devices or parts of the electrode devices loaded with a heating current are replaced by circuitry means, a significant increase in the lifetime can be achieved. For example, if the end of the fluorescent lamp at which the electrode device is subjected to a heating current changes with each switch-on process, the lifetime of the fluorescent lamp can essentially be doubled. It is also possible for such a change to be carried out by hand, for example by changing the orientation of the fluorescent lamp in the socket by rotating the fluorescent lamp.

If only one electrode device is heated, the described method operates the fluorescent lamp in a "direct current mode" immediately after ignition. This means that the majority of the electrons only emerge from the heated electrode. If the fluorescent lamp is operated for a longer period of time, however, the unheated electrode can also heat up to such an extent that the fluorescent lamp operates in normal "AC mode" after a burn-in period.

The described control of the electrode device is also possible, with a few exceptions, if a heating coil of an electrode device has already burnt out or shows a contact fault. This makes it possible for fluorescent lamps, which can no longer be operated with known fluorescent lamp circuits, to be used further with the aid of the proposed method.

An advantageous development of the method consists in that the output of the heating current of at least part of at least one electrode device of at least one fluorescent lamp is at least reduced after a period of time, in particular if the ignition device has a defect. In a number of known fluorescent lamp circuits, in particular in those in which glow lamps with a bimetal electrode are used as a quick starter, it is possible that the fluorescent lamp will only be ignited after a relatively long time, or not at all. This can be due to a defect or caused by signs of wear on the quick starter or other components. Especially in the case of rapid starters designed as glow lamps, with such a delayed ignition of the fluorescent lamp, a heating current flows with essentially full power through the electrode devices of the fluorescent lamp over a long period of time, so that they are exposed to great wear. This shortens the life of the fluorescent lamp accordingly. In other words, there is an unnecessary time load on the electrode devices. In contrast, in the proposed development of the method, the heating current is automatically reduced after a certain time or switched off entirely. Between the occurrence of the defect and the repair of the same, there is therefore no or only a slight load on the electrode device. After the repair, the electrode devices are again charged with a heating current at full power. This is preferably done automatically. However, it is also possible for the user to have to actuate a switch device so that the electrode devices are again subjected to a heating current at full power, in particular without first having to wait for components to cool down.

It is also possible for the ignition or the operation of at least one fluorescent lamp to take place at a voltage at the electrode devices of the fluorescent lamp that is higher than the supply voltage of the fluorescent lamp circuit. Of course, both ignition and operation at increased voltage are also possible. With a correspondingly increased voltage, it is possible that the applied electrical power for heating the electrode devices is reduced again. This results in a further reduction in the wear of the electrode devices and thus an additional increase in the life of the fluorescent lamp. In extreme cases, it is even possible to completely dispense with the heating of the electrode devices can be. This makes it possible in particular that even fluorescent lamps in which the electrode devices on both sides of the fluorescent lamp have a defect, for example because the heating filaments of the electrode devices have burnt out, can still be used as lamps. The supply voltage of the fluorescent lamp circuit is usually the usual mains voltages of 230 V / 50 Hz or 110 V / 60 Hz. However, there are also on-board voltages for motor vehicles, such as usually 12 V (automobiles) or 24 V (commercial vehicles), conceivable.

The voltage at the electrode devices of at least one fluorescent lamp during the ignition, during operation or during ignition and operation is preferably at least 400 V, but preferably at least 600 V. These voltages can cause particularly rapid and low-wear ignition or low-wear operation secure the fluorescent lamp. In principle, there is no upper limit on the voltage. However, as the voltage rises, additional or more complex assemblies are generally required or, in the case of particularly high voltages, insulation problems also occur, so that the voltage used to ignite or operate the fluorescent lamp should also not be chosen too high.

It can also prove to be advantageous if at least one fluorescent lamp is operated with a power which is reduced compared to the nominal power of the fluorescent lamp. Due to the associated lower load on the electrode devices, an extension of the operating time of the fluorescent lamp can also be achieved in this way. It is otherwise irrelevant whether the fluorescent lamp is operated at a constant, reduced output or whether the output of the fluorescent lamp is varied flexibly depending on the requirements.

In a further possible development of the proposed method, at least one fluorescent lamp is essentially in one Operated continuously, at least between a darkened position with reduced power of the fluorescent lamp and a bright position, in particular a position with substantially full power of the fluorescent lamp. This type of control results in a lower load on the electrode device by reducing the number of starting processes per unit of time (for example per week or per month). The proposed method is particularly useful when "residual light" is desired. For example, the method could be used particularly advantageously in stairwells or corridors in order to reduce the risk of accidents when the light is suddenly switched off by an automatic timer. While with conventional lighting the lighting is switched off completely, the brightness is only greatly reduced in the proposed method. The way to the next light switch is at least dimly lit so that a significant reduction in the risk of tripping can be achieved. Thus, not only can a longer lifespan of the fluorescent lamp be achieved, but particularly safe operation can also be achieved. The bright position can be the nominal power of the fluorescent lamp or a reduced electrical power of the fluorescent lamp compared to the nominal power.

The power of the fluorescent lamp in the darkened position is advantageously 0.1% to 20% of the power in the bright position. Sufficient heating of the electrode devices in the darkened position can be ensured in this area on the one hand, and on the other hand the electrical power is reduced so much that the energy consumption in the darkened position (in "standby" mode) is relatively low.

The output of at least one fluorescent lamp is preferably reduced by passive, essentially loss-free components, such as in particular controllable capacitors and controllable coils. In this way, a particularly simple and inexpensive construction of the circuit for controlling the fluorescent lamp can be realized. At the same time, the structure has particular advantages, since essentially no active electrical power (due to ohmic resistance) is converted. This results in both low power consumption and low heating of the components. If the components are adjustable, a dimmer can be replaced with them. The passive components mentioned have the additional advantage over conventional dimmers for fluorescent lamps that they do not require radio interference suppression. On the contrary, there is no risk of radio interference from the outset.

A further possibility for the advantageous implementation of the method consists in that at least one fluorescent lamp is subjected to additional heat at least a part of at least one electrode device. Heat is therefore generated by a heat-generating device that is independent of the electrode device. On the one hand, this makes it possible for the heating power to be generated by an individual heat-generating device to be lower. On the other hand, a redundant design is also possible, in which heat-generating devices can fail without falling below the required heating output. In any case, a longer life of the fluorescent lamp can be achieved. In extreme cases, the electrode device can also be heated to the required temperature without the electrode device itself having to provide heating power.

It is particularly advantageous if the additional heat is applied by a component that is independent of the fluorescent lamp. In this case, the heat-generating component can be replaced independently of the fluorescent lamp if it should have a defect. This enables cost-effective continued operation with a reduced amount of waste. In particular, this has to be done under Mercury, which is harmful to the environment and is contained in the fluorescent lamp, cannot be disposed of.

It proves to be particularly advantageous if the additional heat is applied immediately before the ignition process, during the ignition process or immediately before and during the ignition process of the fluorescent lamp or fluorescent lamps. In this case, the thermal load on the electrode devices can be reduced. At the same time, the energy requirement of the luminaire is reduced since the additional heat is only applied in connection with the ignition of the fluorescent lamp, but no longer when the fluorescent lamp has already ignited and the additional heat is no longer required. However, it is also possible to carry out the additional heat application while the fluorescent lamp is in operation. The latter can be useful, for example, in the case of particularly cold outside temperatures with fluorescent lamps located outdoors. Incidentally, it would also be conceivable to make the additional heat exposure dependent on the ambient temperature, which can be done, for example, by temperature sensors or by a simple PTC resistor (positive temperature coefficient).

It is also particularly advantageous if status information about the operating status of the fluorescent lamp circuit, in particular status information about errors that occur, is output. Such a status information can also inform a layperson of the presence of a defect. The display can also provide information as to whether a specialist has to be called in for repairs or whether a handle that can also be carried out by a layperson is to be carried out, such as changing a fluorescent lamp or changing a starter cartridge. However, it is also possible for the status information to provide further information which provides the expert who is to carry out the repair with information about the cause. the problem so that the repair can be carried out more quickly.

It is advantageous if the status information is output optically, in particular by light emission. This makes it easy to read the information without, under certain circumstances, first having to connect measuring devices or other readout devices to the corresponding device. Light signals also have the advantage that, on the one hand, they are sufficiently conspicuous, but on the other hand they do not have an excessively disruptive effect over a longer period of time, as would be the case, for example, with an acoustic signal.

A further advantageous possibility for carrying out the method is that a plurality of fluorescent lamps are connected in series, wherein in the series connection consisting of fluorescent lamps only a part of the electrode devices of the fluorescent lamps is subjected to a heating current, in particular only the two outermost electrode devices of the series connection. Because only a part of the electrode devices has to be supplied with a heating current, the average wear of the electrode devices is reduced, as already described, so that an overall longer life expectancy of the arrangement can be achieved. This method is particularly advantageous if two fluorescent lamps are connected in series. A particular advantage of the method is that it can be used in connection with existing fluorescent lamp circuits. If, for example, a fluorescent lamp circuit is used to control a 1,200 mm fluorescent lamp instead of the 1,200 mm fluorescent lamp, two fluorescent lamps connected in series, each with a length of 600 mm, are used and the electrodes on the outside of the fluorescent lamps are controlled in the same way as the electrodes of the 1,200 mm fluorescent lamp on, the fluorescent lamp circuit can be operated without any other Specification can be reused A particularly cost-effective changeover to a construction corresponding to the present invention is thus possible.

The method according to one of claims 1 to 15, in particular the method according to one of claims 2, 4, 5, 10, 11, 12 or 15, is particularly advantageously applicable to fluorescent lamps in which at least parts of the electrode device are on at least one side of the Fluorescent lamp has a defect. Such fluorescent lamps can no longer be used in conventional luminaires since, due to a defect in even part of an electrode device of the fluorescent lamp, there is no longer a closed heating current circuit. Ignition of the fluorescent lamp becomes impossible. So far, such fluorescent lamps have been thrown away, although they could still be used in combination with the proposed method or with one of the devices described below. Significant cost savings and a reduction in the amount of hazardous waste can thus be achieved. Fully functional fluorescent lamps can of course also be operated using the proposed method. The proposed method also has its advantages here.

A fluorescent lamp circuit for operating fluorescent lamps, in particular for the advantageous implementation of the method described above, is characterized in that the fluorescent lamp circuit has at least one current-limiting device which controls the electrical current, in particular a heating current, through at least parts of at least one electrode device with respect to the electrical power , the length of time, or both. With such a current limiting device it can be achieved that the load on the relevant parts of the electrode device caused by the electric current of at least one fluorescent lamp is achieved by reducing the time load. tion, a reduction in electrical power, or both. The advantages already described can thus be achieved. In particular, with a corresponding design of the fluorescent lamp circuit, conventional standard fluorescent lamps can be used, so that a particularly simple and inexpensive change to the new technology is possible.

It is advantageous if at least one current limiting device is designed as a continuous current protection circuit in the fluorescent lamp circuit, in such a way that the heating current is at least reduced by at least parts of at least one electrode device of at least one fluorescent lamp after a period of time, in particular in the event of a defect in the ignition device of the fluorescent lamp , This development of the fluorescent lamp circuit enables the advantages already described in connection with the method to be achieved. If one speaks of a time span in this context, this does not mean that the physical parameter in question must necessarily be time. Rather, other underlying parameters are also conceivable, which can also correlate directly or indirectly with time, but do not necessarily have to. For example, a timer can be used that switches off the heating current after several minutes. However, the continuous current protection circuit can also have a light-sensitive element which is used to check whether the fluorescent lamp is on or not.

A particularly simple design of the current limiting device is obtained if the continuous current protection circuit has at least one temperature-sensitive resistance device, in particular a temperature-sensitive resistance device, the electrical resistance of which increases with increasing temperature. Such a temperature-sensitive resistance device can absorb the heat generated in the electrode device by the heating coil or the heat generated by losses register as a sensor device, for example. This sensor information can be processed further in an appropriately designed assembly. However, the resistance device can also directly reduce the heating current through the electrode device as a current-limiting element. In particular, the temperature-sensitive resistance device can be designed as a so-called PTC resistor (PTC for positive temperature coefficient) and can simply be looped into the heating current circuit. If the fluorescent lamp does not ignite, the initially continuous heating current heats up the resistance device, thus increasing the electrical resistance and thereby in turn limiting the current flowing in the heating current circuit.

It is also advantageous if the current limiting device is designed as a bypass circuit such that, in the case of at least one fluorescent lamp, heating current is applied to at least parts of the electrode device located there at most on one side. With this design of the fluorescent lamp circuit, if a heating current is applied to an electrode device on one side of a fluorescent lamp, the fluorescent lamp, as already described, is operated in "direct current mode" at least during and immediately after the fluorescent lamp is ignited. A great advantage of this fluorescent lamp circuit is that fluorescent tubes previously considered defective can largely continue to be used.

The design as a bypass circuit can be implemented particularly easily if the bypass circuit has an electrical connection of contacts of the electrode device, in particular a short circuit of the contacts, on one side of at least one fluorescent lamp. In this case, it is irrelevant whether the electrode device on the relevant side of the fluorescent lamp has a defect, in particular an interruption, or not. The heating circuit itself is not interrupted by the defect in the electrode device.

It is also particularly advantageous if at least one bypass circuit is designed as an automatically recognizing bypass circuit, such that the automatically identifying bypass circuit automatically controls the electrode device on the corresponding side of the fluorescent lamp in the event of a defect in at least parts of the electrode device located on one side of the fluorescent lamp. In this case, it is not necessary that fluorescent lamps in which an electrode device has a defect on one side of the fluorescent lamp have to be installed in a certain direction. In this way, greater usability of the fluorescent lamp circuit can be achieved. The further development mentioned is also advantageous if, in the case of a brand-new fluorescent lamp, a heating coil burns out on one side of the fluorescent lamp after a long period of operation. In this case, the automatically recognizing bypass circuit changes the sides of the fluorescent lamp automatically if necessary, so that the fluorescent lamp can continue to be used without any action by the user.

A further advantageous embodiment of the current limiting device is when the current limiting device is designed as a voltage increasing device in such a way that the ignition process or the operation of at least one fluorescent lamp takes place at an electrical voltage which is higher than the supply voltage of the fluorescent lamp circuit. Of course, it is also possible for both the ignition process and the operation of the fluorescent lamp to take place with an electrical voltage that is higher than the supply voltage of the fluorescent lamp circuit. As already explained in the proposed method, the presence of such a voltage increasing device can likewise reduce the wear on the electrode devices of fluorescent lamps become. In an extreme case, it is also possible for the bypass circuit to be designed in such a way that no heating current is applied to any of the electrode devices of a fluorescent lamp. This means that fluorescent lamps can also be used in which the electrode devices have a defect on both sides of the fluorescent tube. In the case of such fluorescent tubes, it is particularly expedient that they are driven with a power which is lower than the nominal power of the fluorescent lamp, since they otherwise only have a relatively short remaining service life. If, on the other hand, they are operated with a maximum output of 25% of the nominal output, for example, even fluorescent lamps in which the electrode devices have a defect on both sides can still be operated with a remaining service life of up to several thousand hours. Irrespective of a possible defect in one or more electrode devices, particularly rapid ignition of the fluorescent lamp can be achieved if a voltage increasing device is present. The well-known and often annoying repeated flickering until the fluorescent lamp is finally ignited does not apply in this case.

If at least one voltage increasing device has at least one voltage multiplier circuit, a particularly simple construction of the fluorescent lamp circuit can be made possible. If a known voltage multiplier cascade is used, simple and inexpensive components, namely essentially an arrangement of diodes and capacitors, can be used to achieve a voltage doubling, tripling, quadrupling, etc. in a simple and inexpensive manner. With an appropriate design of the voltage multiplier cascade, the fluorescent lamp circuit can therefore be adapted to different supply voltages, in particular to the commonly used mains voltages of the power networks (for example 110 V / 60 Hz in the USA, 230 V / 50 Hz in Europe), using simple means become. A voltage multiplier Cherkaskade can also be achieved by a suitable circuit of a rectifier with capacitors.

It is also advantageous if, in the case of the fluorescent lamp circuit, at least one current limiting device has at least one additional heating device which, in at least one fluorescent lamp, applies heat to at least parts of at least one electrode device. With such an additional heating device, it is possible, on the one hand, that the relevant parts of the electrode devices can be subjected to a lower heating current. In particular in the case of fluorescent lamps to be installed outdoors, such as, for example, street lamps, such an additional heating device can prove to be advantageous, especially at particularly low outside temperatures. It is also possible that the additional heating device or the additional heating devices can act redundantly to the heating device of an electrode device. The circuit can be designed in such a way that a single remaining heating device can bring about the necessary heating of the electrode device to ignite the fluorescent lamp. In any case, a significant increase in the life of the fluorescent lamp can be realized. It is particularly advantageous to provide such an additional heating device in the case of curved fluorescent lamps in which the two electrode devices of a fluorescent lamp are located adjacent to one another (for example in the case of circular fluorescent lamps or in energy-saving lamps). In this case, only one additional heating device can heat several electrode devices.

It is particularly advantageous if, in at least one fluorescent lamp, at least parts of at least one additional heating device are designed independently of the fluorescent lamp. In the event of a defect in the additional heating device, it can be replaced as a single component without the need to change the fluorescent lamp. This means that lower repair costs can be realized. The amount of waste generated can also be reduced.

It is advantageous if at least one additional heating device of at least one fluorescent lamp has a temperature-dependent resistance device, in particular a temperature-dependent resistance device, the electrical resistance of which increases with increasing temperature. With such a temperature-dependent resistance device, the additional heating device can be brought to the required temperature particularly quickly. After the temperature has been reached, the heating current can be reduced by means of the temperature-dependent resistance device. In the simplest case, the temperature-dependent resistance device itself can serve as an additional heating device. However, it is also conceivable that the temperature-dependent resistance device only serves as a sensor. Finally, it is also possible to provide additional control elements that, for example, switch off the additional heating device after a certain period of time.

It also makes sense if at least parts of an additional heating device of at least one fluorescent lamp are connected in series with at least parts of at least one electrode device of at least one fluorescent lamp. In this case, when the heating current flowing through the additional heating device is reduced, the heating current flowing through the electrode device is also automatically reduced. The same applies if the heating current flowing through the additional heating device or through the electrode device is switched off.

In this context, a series connection is also to be understood when the additional heating device is connected in parallel with other components, for example a capacitor, and this parallel arrangement is connected in series with at least parts of at least one electrode device. In this case too, at least part of the heating current flows through the additional heating device, so that the current flowing through the additional heating device is correlated with the heating current flowing through the electrode device.

Furthermore, it is advantageous if at least one current limiting device is designed as a power limiting device, in particular as a controllable power limiting device, in such a way that at least one fluorescent lamp is operated with a power which is lower than the nominal power of the fluorescent lamp. By reducing the maximum permissible output of at least one fluorescent lamp compared to the nominal output of the fluorescent lamp, the life of the fluorescent lamp can be extended. As already stated, this applies in particular when one or more electrode devices have a defect or signs of wear. If a controllable power limiting device is provided, it can also be used as a dimmer in addition to its function as a wear-reducing device. For this purpose, a remote control option, which is not detailed here, can be provided, so that the fluorescent lamp, as in the case of known dimmers, can be dimmed via a controller located away from the lamp. In any case, an overall simplified structure can be realized with a corresponding design.

At least one power limiting device is preferably formed essentially from passive, essentially loss-free components, in particular controllable capacitors, controllable coils or a combination of controllable capacitors and controllable coils. In this embodiment, a particularly simple construction of the fluorescent lamp circuit can be guaranteed. In addition, since the components are essentially lossless, that is, they do not consume any active power (have no ohmic resistance), low energy consumption can be achieved. The execution with passive components is particularly compared to conventional ones

Dimmers for fluorescent lamps much easier and cheaper. In particular, no special measures for radio interference suppression are required, since high-frequency electrical currents do not necessarily occur.

If at least one current limiting device is designed as a continuous operating device in the fluorescent lamp circuit, such that at least one fluorescent lamp is operated essentially continuously, the fluorescent lamp at least between a darkened position with low power and a bright position, in particular a position with essentially full Power, it is possible to achieve the advantages already described in connection with the proposed method. The bright position can either be essentially the nominal power of the respective fluorescent lamp, but on the other hand it can also be the maximum permissible power of the fluorescent lamp which is lower than the nominal power of the fluorescent lamp.

Analogous to the described method, it is advantageous if the continuous operating device is designed such that the power of the fluorescent lamp in the darkened position is 0.1% to 20% of the power in the bright position.

A further advantageous implementation possibility is that at least one current limiting device is designed as a series connection device, such that a plurality of fluorescent lamps are connected in series, wherein in the series connection consisting of fluorescent lamps only a part of the electrode devices is subjected to a heating current, in particular only the two outermost electrode devices the series connection. In this case, the advantages already mentioned in connection with the method result in an analogous manner.

It is also advantageous if the fluorescent lamp circuit has at least one control device such that an indication of the supply Status of the fluorescent lamp circuit, in particular a malfunction. The advantages already described in connection with the method also result here in an analogous manner.

The control device is preferably designed as an optical device so that it allows visual control. It is irrelevant whether the optical device is self-illuminating or, for example, only reflective. For example, it could also be a raster arrangement of viewing elements, the viewing elements being visible from the outside by means of a suitable device either with a dark-coated side or with a side coated with a bright color.

However, the optical device is preferably designed as a light-emitting device, in particular as an incandescent lamp and / or light-emitting diode. On the one hand, a corresponding design is particularly cost-effective, since the components in question are available inexpensively and can also be controlled in a correspondingly simple manner. In addition, light-emitting devices can also be clearly seen in the dark, which is particularly useful for the proposed application, since if there is a defect in the fluorescent lamp circuit, there may be no more lighting.

In the following, several exemplary embodiments of the invention are illustrated to illustrate the invention and with reference to the accompanying drawings.

Show it:

1 shows a fluorescent lamp circuit with a continuous current protection circuit.

2 shows a fluorescent lamp circuit with a bypass circuit; 3 shows a fluorescent lamp circuit with a continuous operating device;

4 shows a fluorescent lamp circuit with an additional heating device;

5 shows a fluorescent lamp circuit with a combination of continuous current protection circuit, voltage increasing device and continuous operating device;

6 shows a fluorescent lamp circuit with a series circuit device;

7 shows a fluorescent lamp circuit with a continuous current protection circuit, a power limiting circuit and an optical control device;

8 shows a fluorescent lamp circuit with a power limiting device and a bypass circuit in which a fully functional fluorescent lamp is used;

9 shows a fluorescent lamp circuit with a series circuit device and a voltage booster device.

A largely individual circuit for fluorescent lamps is shown in FIG. 1. The fluorescent lamp 1 has an oxide electrode 2, 3 at each of its two opposite ends. The oxide electrodes 2, 3 can be heated to a temperature suitable for the emission of electrons by a heating current I flowing through the heating current circuit 11.

Immediately after switching on, i.e. after an AC voltage, for example the usual mains voltage of 230 V / 50 Hz (e.g. in Europe) or 110 V / 60 Hz (e.g. in the USA), to the connections 10 was first applied, the glow lamp 5 serving as starter ignites. Due to the glow discharge in the glow lamp 5, the glow lamp electrodes designed as bimetallic electrodes 6 bend so far that they touch one another. A very strong heating current I then flows through the heating current circuit 11, which heats the oxide electrodes 2, 3 to a temperature suitable for the emission of electrons. In the glow lamp 5, which is now cooling again, the two bimetal electrodes 6 move back to their starting position and thus interrupt the heating current I. This sudden interruption of the heating current I causes a high voltage due to the self-induction in the inductor 4, which ignites the fluorescent lamp. After the gas discharge in the fluorescent lamp 1 has been ignited, it acts essentially as a short circuit, the current through the fluorescent lamp being limited by the choke 4, which acts as a reactance.

However, if, for whatever reason, the fluorescent lamp 1 does not ignite, the glow lamp 5 ignites again, whereupon again a strong heating current I flows through the heating current circuit 11, which heats up the oxide electrodes 2, 3 again. In the case of a classic individual circuit, this process would be repeated over and over again, which would lead to excessive wear of the oxide electrodes 2, 3. To prevent this, a continuous current protection circuit 13 is looped into the heating circuit 11 in the present circuit. The continuous current protection circuit 13 consists of two branches 14, 15 connected in parallel. The first branch 14 consists of a PTC resistor (positive temperature coefficient). In the second branch 15, a PTC resistor 8 and a capacitor 9 are connected in series. If the fluorescent lamp 1 does not ignite, the heating current I heats up the PTC resistor 7. This heating produces an increase in resistance in the branch 14 of the continuous current protection device 13, which leads to a reduction in the heating current I in the heating current circuit 11. By reducing the heating current I in the heating circuit 11, the wear the oxide electrodes 2, 3 significantly reduced in the case of a non-igniting fluorescent lamp 1.

The capacitor 9 is selected such that essentially no current flows through the second branch 15 even when the glow lamp 5 is short-circuited. The PTC resistor 8 consequently does not heat up significantly, and is therefore still conductive. In the event of a very short power failure, a current can flow through the second branch 15 when the oxide electrodes 2, 3 are still hot, which is not sufficient for effective heating of the two oxide electrodes 2, 3, but is strong enough that with a functional glow lamp 5 the fluorescent lamp 1 can be ignited.

Of course, other circuitry measures are also conceivable which reduce or completely prevent a continuous heating current I in the heating current circuit 11 in the case of a non-igniting fluorescent lamp 1.

FIG. 2 shows an example of a fluorescent lamp circuit that has a bypass circuit. The fluorescent lamp 16 has a functional oxide electrode 18 on a first side and a defective oxide electrode 17 on a second side opposite the first side. In the case of the defective oxide electrode 17, the electrode wire has burned out at one point, so that the electrical connection between the two connection pins on the second side of the fluorescent lamp 16 is interrupted. In the bypass circuit, the two connecting pins 19 on the second side of the fluorescent lamp 16 are short-circuited by a connecting line 20, which is attached outside the fluorescent lamp. Despite the defective oxide electrode 17, the heating current circuit 21 is therefore closed via the bypass line 20, so that "a heating current I can flow through the heating current circuit 21. The heating current circuit 21 also leads through a choke 22, through an electronic starter 23 and through the Functional oxide electrode 18. Immediately after switching on ten, that is, after an AC voltage has been connected to the connecting terminals 24, a strong heating current I first flows through the heating current circuit 21 and heats the functional oxide electrode 18 to a temperature sufficient for the emission of electrons. This temperature is reached after a shorter period of time and the electronic starter 23 generates a high ignition voltage between the functional oxide electrode 18 and the defective oxide electrode 17. The polarity of the voltage is important here. Since only the functional oxide electrode 18 has a temperature sufficient for the emission of electrons, the negative polarity must be applied to the functional oxide electrode 18, while the positive polarity is applied to the defective oxide electrode 17. The fluorescent lamp 16 now ignites and begins to light up. The electronic starter 23 then switches off the heating current I. In the first time after the ignition, there is only an electron leak in the direction of the arrow labeled e ^" . After a certain period of operation, however, the defective oxide electrode 17 can also heat up to such an extent due to heat loss that it too has an emission of electrons has sufficient temperature.

With the circuit arrangement shown in FIG. 2, it is possible that fluorescent lamps previously considered defective, in which the oxide electrode on one side of the fluorescent lamp has blown, can continue to be used. In a further development of the circuit arrangement shown in FIG. 2, which is not detailed here, a switchable bridging line is provided on each side of the fluorescent lamp 16, the switchable bridging lines being switched by an automatic control in such a way that it is automatically determined whether and if so on which one There is a defect in the oxide electrode on the fluorescent lamp side. This can be done, for example, by a continuity test. The automatic control, not shown here, then causes the switchable bypass line on the corresponding side of the fluorescent lamp 16 to be closed and the electronic starter 23 applies the ignition voltage generated by it with the correct polarity to the fluorescent lamp 16.

3 shows a fluorescent lamp circuit having a continuous operating device. The heating current circuit 34 consists of a choke 29, a first oxide electrode 32, a glow lamp starter 30 with a starter capacitor 31 connected in parallel therewith, a second oxide electrode 32 of the fluorescent lamp 25 and a continuous operation control 26. As soon as the AC voltage required for operation is applied to the connection terminals 35, it ignites the fluorescent lamp 25 according to the description given in connection with FIG. 1. In a departure from the circuit shown in FIG. 1, the present heating current circuit 34 has a continuous operation control 26 instead of the continuous current protection device 13 (FIG. 1). In the present case, the continuous operation control 26 is constructed from two branches connected in parallel. The first branch has a current limiting device designed in the present case as an adjustable capacitor 27. The second branch of the continuous operation control 26, which is connected in parallel, consists of a switch 28. If the switch 28 is in the closed position, as shown, the fluorescent lamp 25 is essentially operated with the nominal power of the fluorescent lamp 25. The fluorescent lamp shines with maximum brightness. Instead of switching off the fluorescent lamp, for example by disconnecting the mains voltage, the switch 28 is opened so that the fluorescent lamp is then in a darkened position. Because of the adjustable capacitor 27, a lower current now flows through the gas discharge ignited in the fluorescent lamp 25, so that the fluorescent lamp 25 only shines with a lower brightness. A suitable power value for the darkened position is, for example, 0.1 W. By means of the adjustable capacitor, the luminaire can be individually adjusted to the desired residual power or residual brightness in the position with low brightness during installation can be set. The value of the capacitor depends on the shape, design, length and thickness of the fluorescent lamp 25 used.

Such continuous operation with a darkened position is useful, for example, for stairwells or corridors. If the time period set on a time switch has expired, the stairwell lighting is not switched off completely, but is only switched to a darkened state. This means that at least an orientation is still possible for a person in the stairwell. In addition, the circuit shown in FIG. 3 largely eliminates the on and off operations of the fluorescent lamp 25, so that the oxide electrodes 32, 33 have to be supplied with a heating current I much less frequently, and the life of the fluorescent lamp can thus be significantly increased.

Of course, it is also possible that a staircase switch darkens the lighting during normal office hours, whereas at night and on weekends the lighting is switched off completely to save energy. Because the glow lamp starter 30 is still present, the fluorescent lamp can be ignited for the first time on the morning of a working day or even after a power failure.

4 shows a fluorescent lamp circuit with an additional heating device. The heating current circuit 39, through which a heating current I runs during the switch-on process, consists in the present circuit of a choke 45, a first oxide electrode 37, an electronic starter 44, a second oxide electrode 38 and a PTC resistor 43. In parallel with the PTC resistor 43, a second branch 41 is connected to a capacitor 42. The capacitor 42 serves to allow a minimum of current to flow so that the fluorescent lamp can ignite. In the PTC resistor 43, electrical energy is converted into thermal energy. The heat generated there is used for additional heating of the oxide electrodes 37 and 38. PTC resistor 43 and oxide electrodes 37, 38 are matched in such a way that the oxide electrodes 37 and 38 are loaded as little as possible. After the temperature of the oxide electrodes 37 and 38 required for the emission of electrons has been reached, the electronic starter 44 applies an ignition voltage to the two oxide electrodes 37, 38, so that a gas discharge is ignited in the fluorescent lamp 36.

In the example shown in FIG. 4, a curved fluorescent lamp is used as the fluorescent lamp 36, as is used for example for so-called energy-saving lamps or also for street lamps. Due to the curved shape, as can be seen in FIG. 4, it is possible for a single additional heat-generating PTC resistor 43 to heat both oxide electrodes 37, 38. Of course, appropriately adapted circuits for elongated fluorescent lamps are also conceivable.

While a selection of possible implementations of the invention was shown individually in FIGS. 1 to 4 described above, the fluorescent lamp circuit shown in FIG. 5 shows a combination of several possible implementations of the present invention, which complement one another in a meaningful manner.

The circuit shown in FIG. 5 has a bypass circuit 51, a voltage doubler circuit 55, which also serves as an electronic igniter, and a continuous operation control 56. The fluorescent lamp 47 can be switched between a bright and a darkened position via the light-dark switch 61 of the continuous operation control 56. In addition, a power switch 57 is provided, with which the fluorescent lamp 47 can be switched off completely. The voltage doubler circuit 55 essentially consists of a bridge rectifier 64 and two capacitors 65, 66. In addition, a PTC resistor 62, 63 is in each case connected in series with the capacitors 65, 66. When the fluorescent lamp 47 is switched on, the PTC resistors 62, 63 are still cold, so that they do not influence the capacitors 65, 66. The assembly 55 thus doubles the voltage. After a certain operating time of the circuit, the PTC resistors 62, 63 heat up, so that their resistance increases and the voltage increase is reduced. This reduces flickering of the fluorescent lamp 47.

The fluorescent lamp 47 is ignited by means of the bypass circuit 51 on both sides of the fluorescent lamp 47 without even an electrode 48, 49 being electrically heated before the ignition. The ignition and the operation of the fluorescent lamp 47 are therefore only possible due to the voltage increase by the voltage doubler circuit 55. The bypass circuit 51 is designed in such a way that the connection pins of the two oxide electrodes 48, 49 present on each side of the fluorescent lamp 47 are electrically connected to one another by a bypass 50. With the structure shown, it is possible that fluorescent lamps 47 can continue to be used in which both oxide electrodes 47, 48 have a defect. In this case, it is usually advisable to operate the fluorescent lamp with a reduced power compared to the normal nominal power, so that the fluorescent lamp has a sufficiently long remaining service life.

The circuit described can of course also be modified so that the oxide electrodes 48 and 49 are heated before the fluorescent lamp 47 is ignited. This can either be done by the oxide electrodes 48, 49 themselves, provided that they are not defective, or else by additional heating elements. 6 shows a fluorescent lamp circuit in which two fluorescent lamps 52, 53 are connected in series. In known series connections of fluorescent lamps, a heating current is applied to all oxide electrodes of the fluorescent lamps used before the ignition. In contrast, in the embodiment of the invention shown in FIG. 6, only the two outermost oxide electrodes 69, 70 are heated. The application of a heating current and the generation of an ignition voltage is controlled by a commercially available electronic ballast 68, which is connected to a mains voltage via terminals 67. It is expressly pointed out that the electronic ballast 68 is a commercially available electronic ballast and does not have to be modified. In contrast, the inner oxide electrodes 71, 72 which are electrically connected to one another by a connecting line 54 are not subjected to a heating current. 6 shows the two inner oxide electrodes 71, 72, each with a defect. Fluorescent lamps in which the oxide electrodes have a defect on one side of the fluorescent lamp can thus be used again for this circuit. Of course, fully functional fluorescent lamps can also be used in the context of the circuit shown.

It should be noted that the fluorescent lamps 52, 53 shown in FIG. 6 have a total length that approximately corresponds to the length of a fluorescent lamp to be used with the electronic ballast 68. If the electronic ballast 68 is designed, for example, to operate 1,200 mm long fluorescent lamps, the fluorescent lamps 52, 53 can each have a length of 600 mm.

7 shows a further fluorescent lamp circuit. A controllable capacitor 77 serves as a power limiting device with which the power of the fluorescent lamp 74 during operation compared to that Nominal power of the fluorescent lamp can be reduced. This alone can increase the life of the fluorescent lamp. If, for example, the fluorescent lamp is operated with a maximum output of 75% of the nominal output, the service life of the fluorescent lamp 74 is generally increased to three times the value. Because the adjustable capacitor 77 is designed to be adjustable, the brightness of the fluorescent lamp 74 can additionally be dimmed, so that no complex dimmer suitable for fluorescent lamps has to be used.

The fluorescent lamp 74 shown in FIG. 7 is ignited after the two oxide electrodes 75 have been heated by a heating current I, the ignition voltage, as already described, being generated by a glow lamp starter 81 and a choke 76. The circuit shown also has a continuous current protection circuit in the form of a PTC resistor 78. In addition, the circuit has a light-emitting diode circuit 89 with a light-emitting diode 80 and an associated protective resistor 79 and an additional diode 91.

If the glow lamp starter 81 has a defect, so that there is initially a sustained heating current I, the PTC resistor 78 heats up. Due to the voltage drop associated therewith, a sufficiently high voltage is now present at the two ends of the light-emitting diode circuit 89, so that the light emitting diode 80 emits light. The light-emitting diode 80 thus serves as an optical control device which indicates a fault in the glow lamp starter 81.

Finally, FIG. 8 shows that the invention can also be used together with fluorescent lamps 82 in which both oxide electrodes 83, 90 are still fully functional. As an example, the fluorescent lamp circuit has, in addition to the usual components choke 85 and glow lamp starter 87, an adjustable capacitor 84, which serves as an adjustable power limiting device, and a bypass 88, which is used as a bypass circuit acts on. Compared to a known fluorescent lamp circuit, a first oxide electrode 83 is subject to slightly reduced wear due to the power limitation circuit. A second oxide electrode 90, however, is subject to almost no wear due to the bypass circuit. If the first oxide electrode 83 has a defect due to its wear, the fluorescent lamp can be used further by turning the circuit shown.

FIG. 9 also shows a fluorescent lamp circuit with a combination of a series circuit device 92 and a voltage increasing device 93. The voltage boosting device 93 is constructed as a voltage multiplier cascade from a plurality of diodes 94 and cascade capacitors 95. Since the external oxide electrodes 96, 97 of the series circuit device 92 formed in the present example from two fluorescent lamps 100, 101 are supplied with an increased voltage by the voltage increasing device 93, there is no need for a separate quick starter. The internal oxide electrodes 98, 99 of the fluorescent lamps 100, 101 are connected to one another via a connecting cable 102 such that there is contact between the four connection pins of the internal oxide electrodes 98, 99. In the present example, only the oxide electrode 99 has a defect. However, the circuit enables the fluorescent lamps 100, 101 to be operated even if only the oxide electrode 98 or if both oxide electrodes 98, 99 have a defect or even if both oxide electrodes 98, 99 are functional.

Of course, any other combinations of the various types of embodiment of the invention are also conceivable. Depending on the application, these can have special advantages.

Claims

claims

1. Method for operating fluorescent lamps (1, 16, 25, 36, 47, 52, 53, 74, 82), in particular for increasing the service life of fluorescent lamps, characterized in that the load on at least parts of at least one electrode device (2, 3, 17, 18, 32, 33, 37, 38, 48, 49, 71, 72, 75, 90) at least one fluorescent lamp due to an applied electrical current, in particular a heating current (I), by means of a reduction in the time load and / or a reduction in the electrical power is reduced.

2. The method according to claim 1, characterized in that in at least one fluorescent lamp (16, 52, 53, 82) at most on one side of the fluorescent lamp at least parts of the electrode device (17, 18, 69, 70, 83) located there with a heating current (I) be applied.

3. The method according to claim 1 or 2, characterized g ekennz ei chnet that the power of the heating current (I) at least a portion of at least one electrode device (2, 3, 75) at least one fluorescent lamp (1, 74) is at least reduced after a period of time , in particular if an ignition device (5, 81) has a defect.

4. The method according to any one of the preceding claims, characterized in that the ignition and / or the operation of at least one fluorescent lamp (47) takes place at an increased voltage at the electrode devices (48, 49) of the fluorescent lamp compared to the supply voltage of the fluorescent lamp circuit.

5. The method according to claim 4, characterized in that the voltage at the electrode devices (48, 49) at least one fluorescent lamp (47) during the ignition and / or

Operating is at least 400 V, preferably at least 600 V.

6. The method according to any one of the preceding claims, characterized in that at least one fluorescent lamp (1, 16, 25, 36, 47, 74, 82) with a reduced compared to the rated power of the fluorescent lamp

Performance is operated.

7. The method according to any one of the preceding claims, characterized g ekennz ei chnet that at least one fluorescent lamp (47) is operated essentially in continuous operation, at least between a darkened position with low power of the fluorescent lamp and a bright position, in particular a position with essentially full power of the fluorescent lamp.

8. The method according to claim 7, characterized g ekennz ei chnet that the power of the fluorescent lamp (47) in the darkened position is 0.1% to 20% of the power in the bright position.

, Method according to one of the preceding claims, characterized in that the output of at least one fluorescent lamp (74, 82) is reduced by passive, essentially loss-free components (77, 84), such as, in particular, adjustable capacitors and adjustable coils, is achieved.

10. The method according to any one of the preceding claims, characterized g ekennz ei chnet that in at least one fluorescent lamp (36) an additional heat application (43) at least a part of at least one

Electrode device (38) takes place.

11. The method according to claim 10, characterized in that the additional heat is applied by a component (43, 54) that is independent of the fluorescent lamp (36, 47).

12. The method according to claim 10 or 11, characterized in that the additional heat is applied immediately before and / or during the ignition process of the fluorescent lamps (36).

13. The method according to any one of the preceding claims, in particular according to claim 3, characterized in that status information (80) on the operating status of the fluorescent lamp circuit, in particular status information on errors occurring, is output.

14. The method according to claim 13, characterized in that the status information is output optically, in particular by light emission (80).

15. The method according to any one of the preceding claims, characterized in that a plurality of fluorescent lamps (52, 53) are connected in series, wherein in the case of the series connection consisting of fluorescent lamps only a part of the electrode devices (69, 70) of the fluorescent lamps is acted upon by a heating current is, especially only the two outermost electrode devices of the series circuit.

16. Application of the method according to one of claims 1 to 15, in particular the method according to one of claims 2, 4, 5, 10, 11, 12 or 15, on fluorescent lamps (16, 47, 52, 53), in which at least parts the electrode device (17, 48, 71, 72) has a defect on at least one side of the fluorescent lamp.

17. Fluorescent lamp circuit for operating fluorescent lamps, in particular for performing the method according to one of claims 1 to 15, characterized in that the fluorescent lamp circuit has at least one current limiting device (13, 20, 26, 43, 51, 52, 55, 56, 77, 78 , 88, 84) which have the electrical current, in particular the heating current (I), through at least parts of at least one electrode device (2, 3, 17, 18, 32, 33, 37, 38, 48, 49, 71, 72, 75, 83, 90) at least one

Fluorescent lamp (1, 16, 25, 36, 47) limited in terms of electrical power and / or the duration.

18. Fluorescent lamp circuit according to claim 17, characterized in that at least one current limiting device is designed as a continuous current protection circuit (13, 78), such that the heating current (I) through at least parts of at least one electrode device (2,

3, 75) of at least one fluorescent lamp (1, 74) after passing through a period of time, in particular in the event of a defect in the ignition device (5, 81) of the fluorescent lamp, is at least reduced.

19. Fluorescent lamp circuit according to claim 18, characterized in that at least one continuous current protection circuit (13, 78) has at least one temperature-sensitive resistance device (7, 8, 78), in particular a temperature-sensitive resistance device, the electrical resistance of which increases with increasing temperature.

20. Fluorescent lamp circuit according to one of claims 17 to 19, characterized g ekennz ei chnet that at least one current limiting device is designed as a bypass circuit (20, 51, 88), such that at least one fluorescent lamp (16, 47, 82) at most one On the side of the fluorescent lamp, at least parts of the electrode device (18, 49, 83) located there are subjected to a heating current (I).

21. fluorescent lamp circuit according to claim 20, characterized g ekennz ei chnet that at least one bypass circuit an electrical connection (20, 50, 88) of contacts (19) of the electrode device (17, 48, 90), in particular a short circuit of the contacts, at least one side of at least one fluorescent lamp (1, 47, 82).

22. Fluorescent lamp circuit according to claim 20 or 21, characterized in that at least one bypass circuit is designed as an automatically recognizing bypass circuit, such that the automatically recognizing bypass circuit automatically detects a defect in at least parts of the electrode device located on one side of at least one fluorescent lamp Controls the electrode device on the corresponding side of the fluorescent lamp.

23. Fluorescent lamp circuit according to one of claims 17 to 22, characterized in that at least one current limiting device is designed as a voltage increasing device (55), such that the ignition process and / or the operation of at least one fluorescent lamp (47) in relation to the supply voltage of the Fluorescent lamp circuit increased electrical voltage.

24. The fluorescent lamp circuit as claimed in claim 23, characterized in that at least one voltage increasing device has at least one voltage multiplier circuit (55).

25. Fluorescent lamp circuit according to one of claims 17 to 24, characterized in that at least one current limiting device has at least one additional heating device (43, 54) which, in at least one fluorescent lamp (36, 47), has at least parts of at least one electrode device (38, 49) heat applied.

26. Fluorescent lamp circuit according to claim 25, characterized in that in at least one fluorescent lamp (36, 47) at least parts of at least one additional heating device (43, 54) are designed independently of the fluorescent lamp.

27. Fluorescent lamp circuit according to claim 25 or 26, characterized in that at least one additional heating device of at least one fluorescent lamp (36, 47) has at least one temperature-dependent resistance device (43, 54), in particular a temperature-dependent resistance device, the electrical resistance of which increases with increasing temperature.

28. Fluorescent lamp circuit according to one of claims 25 to 27, characterized in that at least parts of at least one additional heating device (43, 54) at least one fluorescent lamp (36, 47) with at least parts of at least one electrode device (37, 38, 49) at least one fluorescent lamp in Series are connected.

29. Fluorescent lamp circuit according to one of claims 17 to 28, characterized in that at least one current limiting device is designed as a power limiting device (77, 84), in particular as a controllable power limiting device, in such a way that at least one fluorescent lamp with one power is operated, which is lower than the nominal power of the fluorescent lamp.

30. Fluorescent lamp circuit according to claim 29, characterized in that at least one power limiting device consists essentially of passive, essentially loss-free components, such as in particular controllable capacitors (77, 84) and / or controllable

Coils, is formed.

31. Fluorescent lamp circuit according to one of claims 17 to 30, characterized in that at least one current limiting device is designed as a continuous operating device (26, 56), such that at least one

Fluorescent lamp (25, 47) is operated essentially in continuous operation, the fluorescent lamp being changed at least between a darkened position with low output and a bright position, in particular a position with essentially full output.

32. Fluorescent lamp circuit according to claim 31, characterized in that the continuous operating device (26, 56) is designed such that the power of the fluorescent lamp (25, 47) in the darkened position 0.1% to 20% of the power in the bright position.

33. Fluorescent lamp circuit according to one of claims 17 to 32, characterized in that at least one current limiting device is designed as a series circuit device, such that a plurality of fluorescent lamps (52, 53) are connected in series, only a part of the series connection consisting of fluorescent lamps a heating current is applied to the electrode devices (69, 70), in particular only the two outermost electrode devices of the series connection.

34. Fluorescent lamp circuit according to one of claims 17 to 33, characterized in that the fluorescent lamp circuit has at least one control device (80) such that the status of the fluorescent lamp circuit, in particular a fault, is displayed.

35. Fluorescent lamp circuit according to claim 34, characterized in that the control device is designed as an optical device (80).

36. Fluorescent lamp circuit according to claim 34 or 35, characterized in that the optical device is designed as a light-emitting device, in particular as an incandescent lamp and / or light-emitting diode (80).