WO2018162302A1 - Consumer array with temperature self-regulation and method - Google Patents

Abstract

The invention relates to an electrical system comprising a plurality of spatially distributed electrical consumers (1) and a plurality of PTC series resistors (2, 9) which are connected in series with at least a part of the electrical consumers (1). At least a part of the plurality of PTC resistors (2, 9) is in each case arranged in thermal contact with at least a part of the consumers (1). The invention further relates to a method for producing, in particular printing such a system.

Description

 Consumer array with temperature self-regulation and method

The invention relates to a system for the automatic control of a plurality of spatially distributed electrical consumers with regard to their maximum allowable power. In this case, consumers may be, in particular, LED light sources, so-called light engines. Furthermore, the invention relates to a method for producing, in particular for printing such a system.

Light-generating planar or strip-shaped arrangements are known which serve for illumination by means of LEDs mounted on their surface. LED's have known advantages in terms of efficiency, size, life and operating temperature over, for example, incandescent or gas discharge bulbs. LED's are also characterized by a very long life, which is disadvantageously reduced significantly at a little exceeded maximum chip temperature.

In order to derive the inevitably resulting heat output of the LED chip, the LEDs are therefore usually thermally well conductive on a circuit board, which otherwise serves to power the LED's and as a mechanical support applied. The heat is then dissipated there via cooling surfaces to the environment depending on the installation situation more or less well.

If a typical chip temperature is only slightly exceeded permanently over a longer period of time, the lifetime of the LED drops sharply, for example by typically 50% at 10K.

For this reason, the maximum chip temperature must be strictly adhered to, which means that it must not be exceeded at a maximum, defined ambient temperature for the built-in PCB in continuous operation at a defined performance under any circumstances. At this maximum temperature, assuming at the same time the worst possible cooling conditions, the maximum permissible power of the LED and thus of the light module as a whole inevitably has to be aligned. The heat transfer is proportional to the temperature difference between the LED chip and the respective local ambient temperature of the light engine, whereby the respective thermal resistances of the intermediate media add up.

It follows that the maximum power of, for example, 30 watts of given LED at a given Wärmeleitwiderstand the arrangement remains limited by an assumed maximum ambient temperature, for example, permanently 60 ° C. This maximum ambient temperature is an important criterion in the application, but not infrequently leads to application-technical errors, partly due to only locally high temperatures and thus premature partial or total failure.

However, if the ambient temperature is correspondingly lower, such as 25 ° C, the LED array could be operated at a correspondingly higher power, for example 40 watts, and the maximum would be

Chip temperature still not exceeded. It can therefore be a correspondingly higher current, due to the typical characteristic of the LED at a case otherwise hardly increased voltage, are applied, the emitted light power thereby increases approximately proportional to the applied current.

In order to make use of this reserve, according to the state of the art, where this expense is economically worthwhile, the LED current is regulated in accordance with the ambient temperature such that the chip temperature remains within the maximum values. This is usually done with the aid of a local thermal sensor and control electronics, which requires active components such as field effect transistors. A problem with this is the only localized detection of the temperature, assuming that this applies to the entire arrangement. The mentioned problem can also be addressed relatively easily via the ballast, which, however, often arranged relatively far away from the LED's to be monitored and therefore is even more error-prone.

Significantly simpler and cheaper is an arrangement in which a single resistor with a positive temperature coefficient (PTC) in the form of a component the LED series circuit is arranged directly on the circuit board upstream. With constant voltage supply, as the temperature of the PTC rises, its resistance increases sharply in the region of its typical transition temperature, thus increasing the voltage drop across the low-resistance PTC, thus reducing the voltage on the LED chain accordingly, as a result of the typical voltage Current characteristic of a diode thus decreases the current through the LED disproportionately strong, resulting in the result in a correspondingly lower performance in the LED with correspondingly significantly decreasing chip temperature. Since the PTC is located locally near an LED, this arrangement is self-regulating. However, this is only limited because the PTC only reflects the temperature of the locally close LED of the entire chain. However, this is due to the spatially widely distributed arrangement is obviously not satisfactory, a locally for whatever reason occurring heat spot is not recognized, the corresponding LED will fail prematurely and thus the series connection of the entire LED chain.

The characteristic curve of such an automatic passive PTC control can be well adjusted by a series connection of a series resistor for limiting the maximum current and a parallel connection to the PTC for increasing the minimum current within limits.

Disadvantages of this solution are the additional necessary PTC with the appropriate size, so that the control is not affected by the relatively high currents and the resulting self-heating itself - to the PTC must be designed correspondingly large volume, which in turn is associated with considerable effort.

Furthermore, the PTC responds exclusively to the temperature prevailing locally in its immediate surroundings and can however be thermally coupled to at most one of, for example, 12 LEDs connected in series, which is then monitored by way of example under the simplifying and usually erroneous assumption that all the LEDs experience the same cooling. Occurs at non-monitored location but locally a Ubertemperatur, this is not detected, the corresponding LED chip temperature is permanently exceeded and the LED fails accordingly prematurely, which leads due to the series connection to a visually negatively striking failure of the entire chain of LEDs.

It is therefore an object of the present invention to provide a system by means of which a reliable, simple and spatially resolved power control spatially distributed consumers can be achieved, in particular within the same series connection. It is a further object of the present invention to provide a method of making such a system.

These objects are achieved by the system and method having the features set forth in the independent claims. The subclaims relate to advantageous variants and embodiments of the invention.

The electrical system according to the invention, comprising a plurality of spatially distributed electrical consumers such as light sources, in particular semiconductor light sources such as LED's and a plurality of PTC series resistors, which are connected in series with at least a portion of the electrical loads.

According to the invention, at least a part of the plurality of PTC series resistors is arranged in each case in thermal contact with at least one part of the consumers. The arrangement of the series resistors in thermal contact with at least one part of the consumers is to be understood in particular as meaning that changes in the absolute temperature in the region of a consumer within a short time, typically within a few seconds, also manifest themselves as a temperature change in the region of the respective series resistor. This can be achieved, for example, by arranging the series resistors in each case in close proximity to the respective consumer, in particular at a distance of less than 10 mm, preferably at a distance of less than 5 mm. However, the thermal contact can also be achieved by the use of heat-conducting elements, for example of heat pipes, also known as heat pipes. In this case, an immediate neighborhood of series resistor and consumer is not mandatory. Preferably, a thermally coupled PTC resistor is present for each LED of a series circuit.

In this case, advantageously, the PTC series resistors can each be realized on a carrier layer as layers which contain electrically conductive printing ink with PTC properties, also referred to below as PTC printing ink.

For example, the PTC printing ink may be an electrically conductive printing ink originally developed for self-regulating heating structures. There, the heating power, which gives the printed PTC, which is used as a heating resistor, at a constant supply voltage decreases significantly with increasing temperature in the range of a typical transition temperature because of the increase in resistance of the conductive ink. As a result, a largely constant temperature of, for example, 60.degree. C. is established, even with very different heat dissipation or different ambient temperature, as long as the heat dissipation does not fall below a minimum level. Such a printing ink is available, for example, under the trade name LOCTITE ECI 8001 from Henkel AG & Co. KGaA.

In other words, the described PTC printing ink is advantageously used for regulating the electrical load, in particular an LED chain as a function of the chip temperature. When a jump temperature of, for example, 60 ° C. is exceeded, the resistivity of the PTC ink increases by a factor of 7, correspondingly increasing the voltage drop across the PTC series resistor. As a result, at a constant supply voltage, the difference voltage at the consumers drops slightly in the ratio, but due to the typical LED characteristic of the current strong. As a result of the associated power reduction at the LED's, the temperature of the LED chips and thus also of the corresponding locally thermally coupled regions of the PTC printing ink are also reduced.

It has been found to be particularly advantageous that provided with printed PTC ink area by their relatively large surface at at the same time low resistance despite the LED current produce no relevant self-heating, which would otherwise distort the scheme. For this purpose, the PTC printing ink is advantageously applied over a large area. At the same time, this planar arrangement advantageously allows a detection of the temperature of all LEDs of a chain to be controlled simultaneously. This arrangement results in an equivalent circuit diagram, in which a respective PTC series resistor connected in parallel with other PTC series resistors is thermally coupled adjacent to each LED. For this purpose, the PTC series resistors in particular at a distance of less than 5 mm from the respective consumers - for example, the LED's - be arranged.

By the above-mentioned parallel circuit of the PTC series resistors of the necessary low resistance of typically, for example 1 ohms with the per se relatively high-impedance PTC ink with typically, for example

1700Ohm / square @ 25 μιτι layer thickness can be achieved.

Thus, only a local increase in the temperature at an LED leads to a partial increase in the total resistance of the parallel-connected PTC series resistors and thus to a relevant lowering of the temperature of the chain. However, this effect is reduced as the number of LEDs in a chain increases.

If the whole arrangement is uniformly too warm, the current is correspondingly reduced significantly, it establishes a stable temperature equilibrium, which is not directly at the absolute ambient temperature or the absolute

Cooling, but properly at the temperature near the LED and thus the LED chip aligns. For a much better monitoring of the temperature of each LED chip of the arrangement is achieved as previously possible according to the prior art.

In an advantageous variant of the invention, the PTC series resistors are arranged between the teeth of a spatially extended comb-shaped conductor structure and can in particular be realized as rectangular, in particular square, areas of applied printing ink. In other words, the desired relatively low parallel resistance created by the fact that the electric current is passed over the inter-teeth of two realized as copper layers, opposing combs. The teeth of the opposite combs are electrically connected exclusively by the PTC ink, which can be realized simultaneously with a simple printing process.

In the context of the present invention, "different PTC series resistors" are to be understood as meaning, in particular, different regions of a contiguous layer of a PTC ink.The differentiation into a plurality of different regions then results from the spatial proximity or the thermal coupling to or with a consumer.

The layer thickness of the printing ink may, in particular, be in a range from 15 μm to 30 μm, in particular in a range of 25 μm.

Since the PTC printing ink has a relatively high resistivity of typically 1.7 kOhm for each square at the usual printable layer thicknesses of, for example, 25μηη, in order to achieve the necessarily low resistance of, for example, 1.7 ohms set forth above 1, 000 squares needed. Advantageously, this is achieved by the above-mentioned comb-like toothing in the layout. This structure is advantageously applied in parallel and as close as possible to the LEDs of the corresponding row in order to achieve the best possible thermal coupling between the corresponding areas of the PTC printing ink and the corresponding LEDs.

This coupling is preferably further improved in that the carrier layer, for example a printed circuit board, with a very large, thermally highly conductive layer, in particular a metallic layer using, for example, copper or aluminum on the thin carrier material with a thickness of, for example, 10 50μηη is running.

An additionally applied to the conductor layer on the underside of the carrier layer or the printed circuit board copper layer to further improve thermal coupling between LED and PTC. Under the underside of the carrier layer is understood to be the consumer side facing away from the carrier layer.

This lower copper layer can advantageously be full surface and thus conduct thermally well, since it has no current-carrying function. It also compensates for any local temperature differences.

In an advantageous alternative embodiment, the above-mentioned comb structure, together with the regions of the PTC printing ink, can also be arranged on the underside of the carrier layer. In this case, only the corresponding plated-through holes are still to be provided to the side of the carrier layer, on which the consumers are arranged. This embodiment of the invention has the advantages that, on the one hand, the regions of the PTC printing ink can be arranged exactly on the side of the carrier layer opposite the consumers, so that the thermal coupling between the LED chip and PTC printing ink is optimized, thereby improving the response of the Systems should improve. On the other hand, the conductive, for example, comb-shaped copper structure in this case can be designed geometrically such that it can additionally perform the function of heat distribution on the underside of the carrier layer. On the top side of the carrier layer, only the consumers would then have to be contacted by means of suitable conductor tracks. Such a solution may be advantageous, in particular, for application situations in which there is insufficient space available for the comb-like conductor structures mentioned above, for example when the electrical consumers are arranged in a single series connection one behind the other, as may be the case with LED light bands ,

The regions of the PTC printing ink can preferably also be electrically isolated from the latter in the layout at larger grid spacings of the consumers or the LEDs, but can be arranged only in the immediate vicinity of each consumer; only the minimum necessary current supply to the LEDs limit this arrangement. To save material of printed circuit board matehal usually flat light engines are often divided into non-continuous surfaces, for example by division by means of a punching. For the realization of the invention, however, a coherent large-area conductor structure is preferably used as the carrier layer.

This can preferably be realized in the form of a thin PET conductor foil, which can be coated on one or two sides with copper. The conductor foil may in particular have a thickness in the range of 20μηη-10Όμηη, in particular in the range of 50μηη. Since the material costs are significantly reduced compared to conventional printed circuit boards, a correspondingly large surface area is available cost-effectively, which is not technically required for the basic function of a light engine for the power supply and carrier function.

This free area can preferably be used for the areas with PTC printing ink.

The additional pre- or parallel resistances in the range of typically 1... 10 ohms, which supplement the PTC regions, can preferably be generated in the layout of the copper interconnects instead of by discrete components through thin meander-shaped structures, which eliminates the need to additionally assemble them. On the support structure with printed PTC and series resistors, realized in the form of thin interconnects, then only the consumer such. B. to solder the LEDs or glue. The production of layers containing PTC ink is possible simultaneously for all the chains of a light engine with only one printing operation. As a printing method is particularly but not exclusively the screen printing.

In intaglio printing, it is possible to use both conductor track structures for supplying power to the consumer in the form of, for example, silver-containing highly conductive conductive ink and layers containing the PTC ink in one pass in a plurality of printing units at the same time accurately and very quickly To Print. This is particularly advantageous if one prints the structure of the invention in large areas endlessly in roll form on film. Such a film must then be equipped only with the consumers such as the LEDs, more components omitted.

This light foil can be fed with a constant voltage supply in certain lengths, each individual parallel-connected LED chain is thermally protected against overheating by its respective printed PTC series resistors, thus significantly simpler installation conditions for such a foil can be defined. The installation situation and the cooling can vary between very good and minimal, nevertheless, the maximum possible light output of the overall arrangement is achieved due to the automatic control.

In the event that, for example, LED's are also implemented by printing technology, such as in the case of OLEDs, so a self-regulating Lightenginefolie can advantageously be produced entirely purely printing technology, the subsequent assembly of additional electronic components deleted. There are only the appropriate printing units for the different media to be printed, such as the PTC ink, copper or silver for printed conductors and provide the necessary for the realization of the LED's substances.

The PTC inks are announced in addition to the already available version for heating purposes with 60 ° C transition temperature with other transition temperatures of 40, 80 and 100 ° C in data sheets. This results in further optimization possibilities, for example by preferably two different PTC colors being printed in parallel. This results in a transition temperature 1 reduction and ditto then at transition temperature 2 again. Thus, the characteristic of the controller can preferably be better adapted.

On the one hand, several PTC series resistors assigned to different consumers can be connected in series for the circuitry implementation of the solution according to the invention. For example, for an application in a serially connected LED chain, the PTC series resistors can also be connected between see the LEDs of the chain be arranged within the series circuit. It is also conceivable to arrange a plurality of PTC series resistors connected in parallel and spatially and thus thermally to individual loads as a common series resistor circuit in front of these consumers in the current path common to the loads. The consumers can in principle be connected in series or in parallel.

The result obtained, for example, a flat light engine, which automatically adjusts to the respective ambient temperature, the maximum allowable power of the LED's and this taking into account local temperature differences, as for example by different thermally conductive ground or different air supply due to the installation position or by a poor Cooling by ventilation or the like may arise. This optimizes the otherwise massively endangered life of the LEDs in such cases or at affected locations within the light engine.

The regulation is continuous and slow and is therefore not perceived as disturbing. Depending on the design of the resistance values of the layers containing PTC ink and the series resistors, control factors in the range of a few percent to more than 70% can be achieved and thus optimized for a large number of applications, depending on which target is to be achieved with priority.

In other words, it is achieved by the invention that the same LED can be operated at considerably higher powers than unregulated, as long as the cooling by the environment is correspondingly effective. If the ambient temperature increases or the cooling is impaired by any influences, possibly only locally, the performance of each LED chain is automatically reduced with minimal technical effort by the PTC ink applied with only one printing process.

Thus, at favorable thermal conditions, the light output of otherwise identical LED's compared to a conventional solution without control clearly increases, especially since the conventional solution must be based on the respectively defined maximum allowable ambient temperature - usually on the assumption that the local cooling is identical for all consumers, but in practice in some cases does not apply. This then leads to corresponding premature failure of individual LEDs and thus because of the series connection of the complete respective affected LED chain total to a corresponding negative effect for the user or vice versa analog increased warranty for the manufacturer, since such errors due to the inadequate operating environment very difficult are detectable.

This is particularly because, as is known, the preservation of evidence in the case of premature failure of LED bulbs due to overheating is a common problem. If one can avoid the problem of thermally induced failures using the invention in principle, resulting from the average of all applications significantly longer life and obviously many other economic benefits.

An advantageous application of the solution according to the invention can be carried out in so-called retrofit fluorescent tubes. In such tubes, an elongated printed circuit board with LED's is mounted in series in a glass tube so that the tube can be used, for example, in a lamp originally intended for a conventional fluorescent tube. Also in this application, a spatially resolved, temperature-dependent power control makes sense.

Embodiments and variants of the invention will be explained in more detail with reference to the drawing. Show it

1 with reference to an equivalent circuit diagram, the principle of the invention, Figure 2 shows an exemplary layout for the realization of the invention, Figure 3 shows an advantageous design concept for the realization of the invention,

Figure 4 shows a variant of the invention, and FIG. 5 shows a further variant of the invention.

FIG. 1 illustrates the principle of the invention with reference to a schematic equivalent circuit diagram. Shown in the figure are a plurality of LED's 1 designed and connected as an LED chain between the two contact rails 3 and 4 in series electrical loads, which are electrically connected via the two series resistors Ri and R ₂ with a DC voltage source not shown separately. Parallel to the series resistor R ₂ and connected to one another are the PTC series resistors 2, one of which is arranged in the example shown in each case in close proximity to each one LED. It is thereby achieved that a similar temperature is established in the region of the respective PTC series resistor 2 with a certain time delay as in the region of the respective LED. In that case, in which the temperature at the location of the PTC series resistor 2 reaches a certain value, the value of the respective series resistor increases abruptly, as a result of which the value of the series resistor of the serially connected LED's increases. Thus, the current is reduced by the respective LED chain with constant supply voltage and the desired control effect adjusts itself. In extreme cases (insulation effect of the PTC series resistors), the maximum series resistance would be R1 + R2. Dashed indicates in the figure is a continuation of the LED chain shown and another, the first chain parallel LED chain.

Figure 2 shows an exemplary layout of the invention. The LEDs 1 are arranged on a thin conductor foil 5 as a carrier layer in a plurality of parallel connected, contacted by means of the first contact rail 3 and the second contact rail 4 chains. Comb-shaped conductor structures 6 extend in the manner described above, between which the desired structure of parallel-connected PTC series resistors can be realized by means of the PTC printing ink already mentioned. In this way, the cheaply available space on the conductor foil 5 can be used in a particularly advantageous manner for the realization of the desired layers of PTC printing ink. With reference to Figure 3, an advantageous design concept for realizing the invention will be explained. Clearly recognizable in the figure are in turn the LEDs 1 and the adjacent comb-shaped structures 6. In the detail enlargement also contained in the figure square areas applied ink 7 can be seen; the arithmetical squares can in particular have an edge length of 1 mm. The quadratic regions can each be regarded as individual PTC series resistors connected in parallel with each other. Hatched in the figure are thermally highly conductive layers 8, which may be formed of copper and are arranged on the back of the conductor foil 5. In contrast to the heating applications known from the prior art, the PTC ink generates little heat, the power loss of the entire PTC area is for example 100mA ^* 2V = 200mW. This leads to a negligible self-heating in the range of less than 0.1 K. Thus, the structure shown senses the ambient temperature near the respective LED 1. The printing ink does not necessarily have to be applied in individual squares; In principle, it is also conceivable to fill the gaps in the structure 6 or other conductive structures with a contiguous area of printing ink.

FIG. 4 shows a variant of the invention in which, compared with the first variant, a local temperature increase in the region of a consumer has a stronger effect by reducing the current through the consumers. In the variant shown in the figure, in each case a PTC series resistor 9 is connected in series in front of the consumers, which are still connected in series, which in turn are configured as LEDs 1. In this case, it is advantageous to select the PTC series resistors 9 at a lower impedance than in the preceding example; here, a value in the range of approximately 0.2 ohm has proved successful. In the case of a uniform heating of the chain corresponding to the individual connected in parallel and thus individual LED's associated PTC resistors 9 effect corresponds to that which is also achieved by the parallel connection of an extended series resistor or a plurality of parallel connected resistors as explained in the previous example , However, in the case shown here, a corresponding local heating in the region of an LED 1 already suffices for the To significantly reduce electricity throughout the chain. In this case, the resistance of the PTC resistor 9 would increase, for example, from 0.2 to 2 ohms, which would have much greater impact on the total current in the entire chain due to the series connection than in the case of several parallel-connected PTC series resistors. The parallel resistors R ₂ ', which can also be seen in the figure, serve to maintain a certain current within the chain in the event that the value of the respective PTC series resistor 9 exceeds a certain value. The resistors R ₂ ', for example, can be realized comparatively easily by meandering conductor tracks and, in particular, have a value of approximately 1 ohm. The series resistor Ri ensures analogous to the previous example that the maximum current through the LED chain remains limited. If the PTC resistor is printed, the desired lower resistance of the individual PTC series resistors leads to a multiplication of the number of required surface elements, for example in the form of squares, given a layer thickness of the PTC color. Thus, this variant is attractive due to the possibly increased space requirement of the individual PTC series resistors especially for applications in which the individual consumers have a greater distance from each other. However, the problem of increased space requirement can be addressed alternatively or additionally by either reducing the lateral dimensions of the individual surface elements or by increasing the layer thickness in which the PTC paint is applied.

5 shows an exemplary detail enlargement of the case in which two different PTC printing inks, in particular with different critical temperature, are used, as indicated in the figure by means of the two PTC series resistors 9 'and 9 ". Series resistor 9 'in the range of 60 ° C, whereas that of the second PTC resistor 9 "may be in the range of about 80 ° C. With a suitable choice, in particular the transition temperatures, the desired thermal behavior of the circuit can be set in a wide range. It goes without saying that more than two different PTC series resistors can be used. In addition, the principle shown in Figure 5 also be applied to other circuit variants, in particular to the embodiments shown in Figures 1 -3 with the necessary changes.

It goes without saying that the invention is not limited to the application for series-connected consumers. It can also be used sensibly for parallel consumers.

LIST OF REFERENCE NUMBERS

1 Electric consumer, in particular LED

 2 PTC series resistor (upstream of several consumers)

3 first contact rail

 4 second contact rail

 5 conductor foil, carrier layer

 6 Comb-shaped structure

 7 area of applied ink

 8 Thermally conductive layer

 9 PTC resistor (assigned to individual consumer)

R2. 2 ^* parallel resistor

 Ri series resistor

 9 ', 9 "PTC series resistors with different transition temperature

Claims

claims 1 . Electrical system comprising  a plurality of spatially distributed electrical consumers (1)  -multiple PTC series resistors (2, 9) connected in series with at least part of the electrical consumers (1),  wherein at least a portion of the plurality of PTC series resistors (2, 9) are each disposed in thermal contact with at least a portion of the loads (1). 2. System according to claim 1,  characterized in that  the PTC series resistors (2,9) are realized as layers respectively realized on a carrier layer (5) and containing PTC printing ink. 3. System according to claim 1 or 2,  characterized in that  the consumers (1) are semiconductor light sources. 4. System according to claim 3,  characterized in that  the semiconductor light sources (1) are LEDs. 5. System according to one of claims 1 to 4,  characterized in that  the thermal contact of the PTC series resistors (2,9) with the consumers (1) is ensured by the fact that the PTC series resistors (2,9) are arranged adjacent to the consumers (1). 6. System according to claim 5,  characterized in that  the PTC series resistors (2,9) are arranged at a distance of less than 5mm from the respective consumers (1). 7. System according to one of the preceding claims 1 -6, characterized in that the PTC series resistors (2) are arranged between the teeth of a spatially extended comb-shaped conductor structure (6). 8. System according to claim 7,  characterized in that  the PTC series resistors (2) are realized as rectangular, in particular square areas of applied printing ink (7). 9. System according to one of the preceding claims 2-8,  characterized in that  the layer thickness of the printing ink is in a range of 15μηη to 30μηη, in particular in a range of 25μηη. 10.System according to one of the preceding claims 2-9,  characterized in that  the carrier layer (5) is provided with at least one additional, highly thermally conductive layer (8). 1 1 .System according to claim 10,  characterized in that  the thermally highly conductive layer (8) as a metallic layer, in particular as a continuous copper layer is formed. 12. System according to one of the preceding claims 2-1 1,  characterized in that  at least a portion of the PTC series resistors (2,9) on the underside of the carrier layer (5) is arranged. 13. System according to one of the preceding claims 2-12,  characterized in that  the carrier layer (5) is designed as a thin conductor foil. 14. System according to one of the preceding claims 2-13,  characterized in that  PTC inks of different critical temperature are present. 15. System according to one of the preceding claims, characterized in that each of the consumers (1) is associated with a PTC series resistor (2,9) which is in thermal contact with it. 16. System according to one of the preceding claims,  characterized in that  several PTC series resistors (9) assigned to different consumers are connected in series. 17. System according to one of the preceding claims,  characterized in that  several PTC series resistors (2) assigned to different consumers are connected in parallel. 18. System according to claim 4,  characterized in that  the system is a retrofit fluorescent tube. 19. A method of printing a system according to any one of the preceding claims,  characterized in that  a plurality of the different components used in a printing operation are printed in different printing units. 20. The method according to claim 19,  characterized in that  all used components are printed in a single printing process.