DE102005006859A1 - Humidification measuring system for use in vehicle, has temperature compensation mechanism providing temperature corrected output signal corresponding to different behavior during change of temperature or humidification condition of areas - Google Patents

Abstract

The system has a sensor unit (100) with two sensor areas and a conductor structure attached to a substrate. A controlling device is coupled with the unit to feed a signal into the unit. A temperature compensation mechanism is coupled with the device and the unit and provides a temperature corrected output signal corresponding to different behavior during temperature change and/or change of humidification condition of the areas. An independent claim is also included for a method of producing humidification state of a sensor unit.

Description

The The present invention relates generally to humidification measurement systems and method, wherein a sensor element with a on a dielectric Substrate applied conductor structure with a corresponding drive circuit is coupled, so that by humidification on the sensor element caused change an inductive component and / or a capacitive component the conductor structure is detectable.

In many areas in the industry, in private households, in the Traffic engineering, for example in vehicles, aircraft and the like, is common a reliable one Determination of the degree of moistening of a surface required, its value then used for further evaluation and / or control of other operations can be. For this purpose, measuring systems with sensor elements are frequently used used, which are designed so that at least one property reproducible under the influence of the degree of moistening to be determined changed from which a signal in dependence the change the degree of moistening is derivable, which in turn then to the other Use available stands. In determining humidification, for example, in Form of water, snow, ice, etc. may be present next to the Aggregate state in particular the amount and their local distribution important in many applications. Among many other applications, such as those on surfaces deposited amount of water in special states of aggregation, for example ice formation on road surfaces, aircraft surfaces and the like, and the detection of rain, water spray or the like for the controller automatic windows and doors, is in particular the application of humidification measuring systems in vehicles for controlling, for example, the windshield wiper system of special Importance.

In some known measuring systems are used especially in vehicles sensors in which the change in the optical behavior of a portion of the windshield due to the fogging with rain or snow measured and the measurement result is used to control the windscreen wiper system. In other known measuring systems sensor types are used, which have a conductive structure with inductive and capacitive component to avoid certain disadvantages of the optical system, so that by moistening the windshield a change substantially the capacitive component and to a very limited extent also the inductive component due the presence of the water, which has a high relative permittivity is caused. The change of the capacitive component of the sensor element thus also changes the frequency behavior of the entire conductor arrangement, which can be regarded as a resonant circuit, so that a measure of the moisture deposited in the vicinity of the sensor element can be derived on account of the displacement of the resonant frequency. In this regard, for example, the document shows DE 10127990 a device for humidification detection, which is constructed according to the resonant circuit principle described above, wherein in particular embodiments are described in which the sensor element with the conductor structure is galvanically decoupled from a corresponding drive circuit and evaluation circuit. Furthermore, this document describes an embodiment in which one or more conductor structures are provided as reference regions, which are less exposed to the influence of humidification, so that an at least qualitative estimation of the amount of moisture deposited on the actual sensor element can be achieved. The provision of one or more reference sensor elements can lead to a greater outlay with regard to the drive circuit and evaluation circuit as well as less flexibility in the division of the area occupied by the sensor elements and their position on the windshield. In particular, it is found that materials used in the windshield of the vehicle, for example, in particular the PVB (polyvinyl butyral) used in the windshield between the two glass layers, which is an amorphous thermoplastic, have relative dielectric constants which are highly temperature dependent. Thus, when changing the temperature of the area of the windshield on or in which the sensor element is mounted, u. U. a greater change in the effective for the capacitive component dielectric constant than is the case for a wetting of the windscreen. Due to this strong temperature dependence of the output signal of the sensor element, it is thus extremely difficult to reliably detect a moistening of the sensor element in the event of changing temperature conditions in the vicinity of the sensor element and thus reliably carry out corresponding control activities. For example, it is extremely difficult in the known measuring systems reliably to trigger a windshield wiper operation when moistened by fog or snow or rain under various practical temperature conditions.

Due to this situation, the object of the present invention is to provide a measuring system and a method based on a Sen To provide sensor element with a ladder structure, wherein a high degree of temperature compensation in the generation of a humidification-dependent output signal is achieved.

According to one First aspect of the present invention, this object is achieved by a temperature compensated humidification measuring system. The measuring system comprises a sensor element with a mounted on a substrate Conductor structure, which is an inductive component and / or capacitive Component, wherein the substrate has a first sensor area and a second sensor area. The first sensor area and the second sensor area carry at a predefined temperature change and / or a predefined change in the humidification state each different to the change the inductive component and / or each different to change the capacitive component at. Furthermore, the system includes a with the Sensor element coupled drive device, which is formed a signal with several, a frequency range with a first bandwidth Feeding defining frequency components in the sensor element. After all the measuring system comprises one with the control device and / or temperature compensation device coupled to the sensor element, which is formed on the basis of different behavior at temperature change and / or changing the Moistening state of the first and second sensor area a the Befeuchtungszu state of the first and / or second sensor area corresponding provide temperature corrected output signal.

By the provision of a sensor element in the humidification measuring system according to the invention, which has at least two areas that change in one the temperature and / or a change in the humidification state different behavior, leaves then by means of the temperature compensation circuit then a corresponding provide corrected output signal. This can, for example the temperature compensation device be such that suitable reference values for the first and the second sensor area previously created and in the Device are stored, which then during the actual measurement process can be compared with the current measured values, in order to be able to also implemented the comparison rule the temperature corrected To produce output signal. In other embodiments, the temperature compensation device additionally to reference values or, alternatively, corresponding calculation rules and related Have resources in the form of software and / or hardware components, in order to have a reference value and thus a temperature corrected Calculate output signal. This can be in the temperature compensation device required effort regarding software and / or hardware components the degree of different behavior of the first and the second Sensor area be determined. So z. B. by structural Activities, d. H. Selection of materials, geometry of the individual sensor areas, their relative position to each other, etc. a desired measure of the different behavior be achieved. It is possible, for example, a relatively high sensitivity for temperature changes in a sensor area, during its sensitivity for humidification can be significantly smaller than the sensitivity for humidification of the second sensor area, such that a substantially the first sensor area attributable response signal as a measure of the temperature of the entire Sensor element can be considered, especially if the construction and / or the position of the first and second sensor areas relative to each other a very similar one Ensure temperature in both sensor areas. In other cases can a distinctly different temperature behavior of the first and the second sensor area in very similar Behavior in response to the same moistening level as well Temperature correction by means of the temperature compensation device be used. Overall leaves So a much more reliable Detection of the precipitation of moisture on the sensor element recognize and thus provide a corresponding output signal, that in turn for further control tasks is available.

In a further advantageous embodiment, the conductor structure is designed substantially as a planar arrangement, so that dimensions in the lateral direction of the conductor structure are substantially greater than a dimension perpendicular to the lateral direction. Due to this design, the sensor element of the moistening measuring device according to the invention can be provided as a flat arrangement, so that it can be applied in particular to exposed surfaces in existing devices and the like. In particular, due to this planar construction, the sensor element of the humidification measuring device according to the invention can be integrated in glass panes and in particular in laminated glass panes, without significantly impairing the overall appearance and the function of the glass pane. The implementation of the conductor structure in a substantially planar arrangement also allows the use of low-cost technologies, such as the lithographic application of suitably arranged interconnect structures. In addition, other methods, for example the application of conductive material, for example wires, to a suitable carrier material by means of gluing, etc. are applied.

In a further embodiment For example, the first and second sensor regions are designed such that the value of the capacitive component changes with temperature in relation to to the total change the sensor behavior changes more than the value of the inductive component.

On that way in extremely effective Detect the presence of water near the conductor structure detect a corresponding increase in permittivity, as before is described. Thus the conductor structure is in a glass pane integrable, without their appearance and functionality worth mentioning to impair wherein due to the inventive design of the sensor areas and the provision of the temperature compensation device the effect a temperature change on the permittivity reliable correctable and possibly highly compensated. Consequently can, while maintaining the measuring principle of a frequency-dependent response to Reason for a change the capacitive component of the optical rain sensors more compact Structure are maintained, the reliability over known Oscillating circuit sensor elements for the moistening detection can be increased.

In a further embodiment the first sensor region has a first dielectric with a first temperature response of a relative permittivity and the second sensor area a second dielectric with a second from the first temperature transition different temperature course of his relative permittivity on. Thus, taking advantage of the influence of the capacitive Component of the sensor element of the humidification measuring device according to the invention an extremely efficient temperature correction take place, the achievable degree of correction u. a. also through structural measures of the sensor element, such as the value of the dielectric constant, the size of the second Sensor area compared to the first sensor area, the geometric Configuration of the conductor structure, which is located in the first sensor area and in the second sensor range can differ and thus in different Contribute to the overall capacitive behavior of the sensor element can be set. This embodiment can be particularly efficient for sensor elements be used, in which at least a portion of the dielectric Substrate in the form of a glass pane, in particular a laminated glass pane is provided, since in this case, as already mentioned, the relative permittivity a strong shows positive temperature response in the second sensor area by incorporating a material of widely varying permittivity into a total clearly recognizable temperature-related behavior of the sensor element leads. For example, a material in one of the two sensor areas be introduced, which has a relative permittivity with negative Temperaturgang has, so that a significantly different Behavior for both Sensor ranges results. If still a very low sensitivity when moistened for one of the two sensor areas by a corresponding structural measure is effected, this results in a response signal that is in very sensitive Way reflects the current temperature of the sensor element and so that a correspondingly efficient temperature correction by means of Temperature compensation device allows.

In a further advantageous embodiment shows the same Humidification per unit area of the first and second sensor regions, the second sensor region a lower influence on the capacitive or inductive component as the first sensor area.

With such a configuration from the second sensor area even more reliable information regarding get the current temperature of the sensor element and thus the Correct the output signal in an efficient way. In these cases can by appropriate arrangement of the conductor structure a corresponding lower sensitivity of the second sensor area when moistened be achieved while the temperature behavior for the first and the second sensor area due to the same Materials and a similar one Position similar to the substrate can be. For example, is through thin tracks a very large parasitic capacitance per unit area can be achieved with very little distance, so that application of water in the vicinity of the conductor structure to a lower relative capacity change and thus a lower sensitivity leads.

In a further advantageous embodiment, a surface wettable by moisture and influencing the capacitive and / or inductive component is smaller in the second sensor region than in the first sensor region. Due to this geometric arrangement, ie, an arrangement with a small "active" sensor surface, a very small "overall response" for precipitated moisture results, in particular in combination with the low sensitivity of this reduced active area, so that a corresponding response signal of the second sensor area is very high efficiently reflects the temperature of the sensor element and thus allows a very efficient temperature correction of the output signal by means of the temperature compensation device. In particular, in cooperation with a lower sensitivity of the capacitive and / or inductive component influencing sensor surface results with this off In this way, a highly effective overall reduction of the sensitivity of the second sensor region to precipitated moisture is achieved, so that, for example, a large difference from the first sensor region with respect to the moistening response is achieved.

In a further embodiment shows at the same temperature change in the first and in the second sensor area, the first sensor area a less influence on the capacitive and / or inductive component as the second sensor area. As mentioned earlier, it may be for efficiency the temperature correction be advantageous when the temperature behavior of the two sensor areas. In the previously described embodiment arises for the first sensor area a lower temperature dependence, such that a response signal obtained from this sensor area is stored in more representative Way for the moistening state of the sensor element can be evaluated, where then the stronger temperature dependence the second sensor area in turn for a more efficient temperature correction is usable. In particular in connection with the previously described embodiment, the lower sensitivity of the second sensor area at Moisturizing describes, overall, an extremely efficient Sensor arrangement, so that correspondingly reliable correction mechanisms can be provided in the temperature compensation device to thus a very reliable temperature correction to reach the output signal.

In A further advantageous embodiment is the conductor structure designed so that a resonant circuit is formed by this with a first and a second by the inductive and capacitive component the conductor structure fixed resonant frequency. By such Configuration of the ladder structure can effectively control the behavior of the Sensor ranges are determined by, for example, the behavior the first and the second resonant frequency is detected. Compared to arrangements in which only substantially one of the two Components a relevant Influence on the response signal, d. h., if no pronounced resonance frequency is present, this represents a very efficient option reading out information from the first and second sensor areas represents.

In a further advantageous embodiment, the conductor structure a first structure and a second structure that are different from each other are galvanically decoupled. In this way, a high degree of flexibility in designing the ladder structure. For example, the first and the second structure are designed so that for the one Structure a high level sensitivity for temperature changes with low sensitivity for the Humidification results while the other structure is also very effective on a change in the dielectric constant by material accumulation reacts, for example, sensitive to the presence of moisture near to display this ladder structure. Furthermore, also by the size of the inductive and / or capacitive coupling of the second structure to the first Structure the position of the individual resonance frequencies and thus the Overall behavior of the sensor element in addition to or as an alternative to others construction measures be set.

In a further embodiment the first structure and the second structure are laterally side by side arranged. With this arrangement can be in a simple manner the degree of mutual coupling as needed in manufacturing of the sensor element vary by, for example, for a given geometric design of the first and the second structure whose lateral distance is adjusted as needed. Furthermore, a Such arrangement also advantageous in embodiments in which several Struktu ren are provided so that these in a simple manner desired Configuration can be arranged side by side. For example, several identical second conductor structures may be provided in area and Sensitivity are different to the first structure, the again a high sensitivity for lowered humidification having. For example, the multiple second conductor structures can be more efficient the temperature distribution at the location of the first structure can be determined without being too big Near and thus coupling the second structures to the first structure required is. That way For example, in a simple way, the temperature behavior of Determine the resonant frequency in the second structure without the second structures have a significant influence on the behavior exercise the first structure. That way you can in a very efficient way, corresponding reference values or reference calculation and / or correction algorithms in the temperature compensation device be stored without significant software and / or hardware resources for consideration a strong mutual influence of the first and second Structures are required.

In a further advantageous embodiment, the second structure laterally encloses the first structure. The sensor element formed in this way thus has a very small size, ie areal extent, compared to laterally juxtaposed structures, so that there is a high degree of flexibility in the positioning of the sensor element. Furthermore, this interleaved embodiment of the first and second structures is highly ge ensures that, at least with regard to the temperature in the first and in the second sensor area almost identical conditions prevail. Therefore, the output signal provided by the temperature compensation means has a high degree of reliability in distinguishing between humidity-related and temperature-related influences.

In further embodiments is the first structure of a single contiguous first Ladder and the second structure from a single coherent built second conductor. A corresponding arrangement can be Produce in a very simple way and can be very efficient in the Production tested By, for example, the ohmic resistance between a Starting range and an end range is measured, so that thereby statements about possible Circuit breaks as well as the size and material composition make the ladder structure.

In a further embodiment The first and second conductors each have parallel or concentric Sections on. With this structure can be a relatively high To achieve conductor track density, so that the parasitic capacitances generated thereby a relatively large Have value, which, for example, the resonance frequencies in a metrologically and with regard to interference radiation easy to handle Set range.

In a further embodiment is the length of the first conductor greater than the length of the second conductor. With this arrangement results in connection with the aforementioned properties thus a relatively large area, the covered by the first conductor which is also a great effective area to disposal is standing on a change the permittivity due to wetting with moisture responds. In contrast, can the second structure due to the smaller length on a smaller one for humidification effective area be applied, where appropriate, the conductor structure by means of very short distances between trains a high capacity and thus low sensitivity can be obtained.

In a further embodiment the substrate is at least partially transparent. To this Way lets the connection according to the sensor element visually appealing in windscreens, headlights, rear windows and the like of vehicles, in windows, glass doors, etc. integrate without the functionality of these facilities worth mentioning impaired becomes. In further embodiments can advantageously also the conductor structure by means of a in the Substantially transparent material to be constructed, so that essentially no impairment the optical function of a transparent substrate results. This is For example, particularly advantageous in applications where the Humidification is determined locally at a certain position, which lies in the direction of a user. For example, it is at Use of the humidification measuring device according to the invention in vehicles advantageous, the sensor element in a range of Windshield position, which is essentially the field of vision corresponds to the driver, so that the control of the windscreen wiper according to the visibility can be done in this area. Conventional rain sensors are typically arranged in peripheral areas of the windshield, so that too often there other conditions in terms of humidity prevail and thus may not cause correct activation of the windscreen wiper. As a suitable material for one essentially transparent conductor structure can be, for example Indium tin oxide can be used, resulting from the production of LED displays is known.

in the further embodiments the substrate forms part of a pane of glass. In such a Arrangement, the conductor structure advantageously in the glass pane be arranged so that there is a surface area, with the environment is in contact and wetted by ambient humidity is. Furthermore, the surface area is arranged in this case that in the first and / or second sensor area an enlargement of the Value of the capacitive component when wetting part of the surface area results. This ensures that the sensor element due to the enlargement of the capacitive component when moisture deposits on at least a part of the glass pane a change in the frequency response learns just because of the different temperature behavior and / or the different behavior in wetting due to Temperature compensation circuit reliable detection of humidification the glass pane is detectable. Through the glass is also a Detecting the precipitated moisture allows without any penetration and thus direct contact of the moisture with the ladder structure is required. This is especially true of Meaning, as the glass län gere After production essentially moisture ingress prevented, so that the moistening of the disc just because of on the surface dejected water is detected and at the same time over a long-term consistent well-defined conditions prevail at the site of the ladder structure. Hereby can by the distance the conductor arrangement to the surface the glass pane a desired Sensitivity can be adjusted.

In advantageous embodiments the glass pane can be formed as a laminated glass pane, the as an intermediate layer comprises an amorphous thermoplastic material. In some embodiments is the amorphous thermoplastic material in the first sensor area and the second sensor area so that for both Sensor areas similar or nearly identical mechanical properties, for example at point load and fracture behavior, result. In this case is the thermal behavior of the two sensor areas similar, so that a corresponding temperature correction by a different Sensitivity to Humidification can be achieved in an efficient manner as this already in previous embodiments explained is.

In In a further advantageous embodiment, the sensor element and the drive device galvanically decoupled from each other. On reason This structure results in a high degree of freedom in the arrangement the control device on the one hand and the sensor element on the other hand, wherein in some embodiments, the one particularly space-efficient Allow arrangement of the first and second sensor area, too a coupling of the first and the second sensor area to each other is provided. Here you can the first and the second sensor area galvanically decoupled from each other be, with the distance between both sensor areas, if this are arranged in a lateral adjacent configuration, in some embodiments can be so small that a noticeable electromagnetic coupling between the two sensor areas, or the distance can be so be dimensioned that no significant superposition of the electromagnetic fields and thus the respective frequency behavior occurs. In the former Trap, which is also an extremely compact Includes arrangement of the two sensor areas, wherein one area at least partially encloses the other, can itself in addition to the compact sensor configuration also certain advantages in terms the drive device, since the sensor element as a coupled Vibration range reacts, so this possibly a lower bandwidth or size for a corresponding coupling coil the drive device may be sufficient. In the latter case The two not significantly coupled sensor areas react relatively independent from each other, so that here with known temperature behavior of Sensor ranges and with sufficiently high diversity of Both sensor areas when moistening with little effort one precise Temperature correction by means of the temperature compensation device can be accomplished.

advantageously, is also the temperature compensation device of the galvanic Sensor element decoupled. With this arrangement, in particular in Connection with the galvanically decoupled control device, let yourself a high degree of flexibility in the Install the humidifier. Especially can thus advantageously the sensor element in glass panes be integrated without any significant changes to the function and the mounting of the glass pane are required because no galvanic connections to the drive device and the temperature compensation device necessary. Furthermore, there is also a high degree of flexibility for the application and the mounting of the humidification measuring device according to the invention, since For example, the sensor element on any components and there can be attached at any position, for example by gluing, adhesion, etc., whereas the driving device and the temperature compensation device spatially separated at a location suitable for them can be provided so that in particular the sensor element extreme environmental conditions can be exposed without the electronic components the drive device and the temperature compensation device also be exposed to these environmental conditions. In this Shape leaves The inven tion proper humidifying network device also perform very efficiently as a mobile unit where the sensor element uncomplicated on any desired component to monitor their degree of humidification is attached, and the drive means and the temperature compensation means are formed so that by appropriate calibration routines the different conditions regarding the distance, the environment, etc. is taken into account. In this case, points the humidification measuring device advantageously also an interface which allows communication with peripheral devices. For example, can the interface be formed, a wireless communication with peripheral devices to enable so that the data obtained by the humidification measuring device for further processing or for Further control processes by the peripheral device without consuming Transfer wiring and can be recycled there.

In a further advantageous embodiment, the drive device is designed to provide the signal with the plurality of frequency components within the predetermined bandwidth so that the frequency components are sequentially fed into the sensor element. In this way, the frequency response of the sensor element can be determined in chronological order, wherein the electronic effort in the drive device remains low and also the required to determine the frequency response bandwidth relatively ge ring can be selected. Thus, for example, a number of different frequency components can be generated with a signal generator whose number and position within the predefined band is sufficient to detect the frequency-dependent response of the sensor element with the desired accuracy, for example resonant frequencies, and on the other hand the required bandwidth to an absolutely necessary one Restrict measurement, so that influencing other electronic components remains low.

In a further embodiment the drive device is formed, the signal with the plurality Frequency components provide so that these simultaneously be fed into the sensor element. For this purpose, for example a ent speaking pulse signal are generated, so that a large frequency range with all the frequency components contained in this frequency range at the same time for the control of the sensor element is ready. In this way let yourself a very rapid detection of the frequency response of the sensor element to reach.

In A further advantageous embodiment is the drive device designed to be a signal with a second bandwidth, the smaller than the predetermined bandwidth is to feed into the sensor element. With this arrangement leaves a higher one Measure flexibility and possibly efficiency for reach the operation of the humidification measuring system, since the feed Signal thus with reduced bandwidth during certain operating phases to disposal can be made. For example, in certain operating phases a scan of the sensor element with a plurality of frequency components be required while In other phases, the now determined frequency behavior for Selection of a few or in particular a single frequency component can now be used with the measuring system via a can be operated for another period. For example, can after sampling the predetermined bandwidth to determine Resonance frequencies then on appropriately selected, in near the Resonant frequencies lying frequency components are switched, making a change the sensor behavior, for example by detecting the signal amplitudes the few selected Frequency components occurs. In other cases, the measurement may be during some Phases with a single frequency component take place, if off the previous measurements with several frequency components one predefined condition for the transition was detected in the single frequency measurement method. During the Measurement with a single frequency component can then be a suitable one elected Abort condition are created, in their fulfillment back into the measurement phase is transitioned to the multiple frequency components.

In According to a further advantageous embodiment, the temperature-compensated Humidification measuring system further comprises a control device, which is formed is to receive the tempera ture corrected output signal and on its basis is a status change effect a device coupled to the control device. With this arrangement leaves the measuring system according to the invention in perform more efficiently than a control unit based on the corrected output signal and thus the degree of moistening the sensor element triggers a corresponding activity. Here, the corresponding status change the dockable device a display device, a servomotor, a processor that uses the output signal for further calculations, and the like. In an advantageous embodiment represents the device is a windshield wiper system of a means of transport, such as a vehicle, a train, etc., so here's the controller the wiper activity dependent on the Befeuchtungszustandes can be done in an automated manner.

According to one Another aspect of the present invention is a method for Generation of a humidifying condition of a sensor element dependent output signal provided, wherein the sensor element has a first and a second Sensor area with one each depending on humidification and temperature a conductor structure produced inductive component and / or capacitive Component has. The method further comprises the steps: Determining a temperature behavior of the first and second sensor area at a sensor state corresponding to a predefined degree of humidification of the first and second sensor regions in response to a feed a drive signal having a predetermined bandwidth; Determine a temperature correction function based on the determined temperature behavior, wherein the temperature correction function at least for the predefined degree of humidification corresponding sensor state a reduction the temperature dependence of the output signal; and using the temperature correction function for generating a temperature-corrected output signal of the sensor element and / or a further sensor element of the same construction based on a Response of the first and the second sensor area to an input Signal with several within the given bandwidth Frequency components.

With this method according to the invention, therefore, the temperature behavior of two sensor regions having different behaviors is first determined. It should be noted that a Tem Behavior in this context is to be understood that a response signal of the sensor element to the feed of the drive signal with a predetermined bandwidth for at least two different temperatures of the first and second sensor area determined and derived therefrom a corresponding behavior of the sensor element at least over a certain desired temperature range becomes. Here, the determination of the temperature behavior at at least two different temperatures may include a metrological and / or a non-experimental extraction of data. For example, by feeding the drive signal, a frequency-dependent response of the sensor element for a predetermined temperature of the first and second sensor region can be obtained and the further behavior, ie a corresponding response of the sensor element for a second or several temperatures can then be determined from data theoretically are known or otherwise determined experimentally. Thus, in the case of a sensor element whose temperature dependence is essentially based on a change in the dielectric constant, the behavior at other temperatures can be determined, provided the temperature behavior of the dielectric constant is known with sufficient accuracy. In other examples, the response signal for a number of different temperatures can be obtained and evaluated, the absolute value of the respective temperature may not be determined, provided that the geometric arrangement of the first and the second sensor region ensures a sufficiently close thermal coupling, so that both sensor areas in Essentially the same temperature.

Out the determined temperature dependence, the for one a sensor state representing a predetermined humidification state applies, for example, a dry NEN sensor state, can then for a suitable Correction of the output signal a temperature correction function, i.e. a rule for linking the determined temperature dependence with the desired Correction history, to be created. In some embodiments can determine the temperature behavior and determine a corresponding temperature correction function once during a Initialization phase or assembly phase are carried out so that the temperature correction function for the Sensor element or other identical sensor elements in corresponding Control devices can be "exported" without that appropriate software and / or hardware resources in the Control device for determining the temperature behavior and the temperature correction function required are. In other embodiments, the determining the temperature behavior and the corresponding temperature correction function be carried out automatically and / or user-initiated, so that a high level reliability the temperature-corrected output signal over a long period of operation can reach the sensor element away. For this purpose can at defined moistening condition, a response signal as required the sensor element with changing Temperature recorded, then, under circumstances consideration an already known temperature correction function and / or other Data, an updated temperature correction function can be created. For this purpose, for example, in the case of using the sensor element as a vehicle rain sensor upon detection of a substantially dry Befeuchtungszustandes or user-initiated, a heating of the appropriate disc are made, so that appropriate temperature-dependent Information can be obtained from the sensor element. In other examples, the temperature behavior over a long period of operation be determined, for example, the temperature correction function to update by the corresponding sensor response signal at dry moistening condition, for example, by request reliable for the user is detectable, is recorded. Especially for vehicles find in the typical applications very many queries very different temperatures, making it an efficient Recording the temperature behavior over a wide temperature range away possible is. For example, if the vehicle control has been decided, that a renewed updating of the temperature correction function desirable is to poll the user every time the vehicle is started, whether the status of the windshield is dry or not. at confirmation a dry state then the corresponding measured value as a measuring point for the recording of the temperature behavior can be evaluated.

In In a further advantageous embodiment, the determining comprises of the temperature behavior: determining a first temperature behavior of the first sensor area at a first predefined degree of humidification corresponding sensor state of the first sensor area in response to the feeding of a first drive signal with a first bandwidth; and determining a second temperature behavior of the second sensor area at a second predefined degree of humidification corresponding sensor state of the second sensor area in response to the feeding of a second drive signal with a second Bandwidth.

This embodiment is advantageous if the first and the second sensor region react to humidification and / or temperature change substantially independently of one another. example For example, an electrical coupling of the two sensor regions can be very small, while a sufficiently high thermal coupling prevails, so that corresponding response signals of the first and second sensor regions can be detected without appreciable electrical interference. In this case, advantageously bandwidths of the corresponding drive signals can be selected in a suitable manner, so that overall a relatively small bandwidth and thus control of other electronic components can be achieved.

In a further embodiment the method further comprises determining a first resonant frequency and a second resonant frequency. Determining a resonant frequency is an efficient means when the sensor areas are pronounced inductive and capacitive components. It should be noted that the term not necessarily determining a resonant frequency includes an exact determination of the resonant frequency, but also includes a determination of a frequency near the resonance frequency, their change with temperature change or change the moistening condition is detectable.

In a further advantageous embodiment, the fed Signal fed without galvanic coupling in the first and second sensor area. As already in previously described embodiments of the measuring system according to the invention is presented, provides a coupling of the signal without cable connection a high degree of flexibility in operation and the assembly of the system.

In a further embodiment is one for Humidification sensitive area and / or a sensitivity for Humidification of the first sensor area smaller than a corresponding one Area and / or Sensitivity of the second sensor area. This can be very efficiently determine a temperature correction function, because the first sensor area has little response to humidification causes a relatively accurate measure of the current temperature of the Sensor area offers.

In further advantageous embodiments are the first and the second predefined degree of moistening equal, being in particular embodiments these moistening levels correspond to a reference moistening level, in which no wetting with liquid of the sensor element is present. Due to the selection of a moistening condition, the for both Sensor elements equal and in particular corresponds to a dry state, can be used in particular for automatically performed or user-initiated Updates the temperature correction function a high degree of accuracy be achieved with little effort.

In a further embodiment The method further comprises determining the behavior of the sensor element at several sensor states, each corresponding to a different degree of moistening. An appropriate procedure can be the accuracy of the temperature correction function improve, especially if the sensor areas a certain degree of electromagnetic Have coupling to each other. For example, a corresponding Behavior at each constant temperature are determined, from which then the corresponding behavior for different temperatures can be deduced or it may be the appropriate behavior for different humidification Temperatures are determined, so that then appropriate temperature behavior for one Variety of different Befeuchtungszuständen present and for derivation the temperature correction function can be used. For example can different "humidifying states" in more reliable and reproducibly "simulated" by correspondingly defined material layers, for example in the form of films, placed on the sensor element with different thickness and / or permittivity in order to determine the corresponding data. To this Way can be a very precise and also economic Creation of temperature correction functions for individual sensor elements respectively.

According to one Another aspect of the present invention is a method for Controlling a device by means of a temperature-corrected output signal provided, wherein the temperature-corrected output signal according to a or more of the foregoing methods. The procedure for controlling the device further comprises setting a condition for the temperature corrected output signal, the condition being a Moisture state of the sensor element corresponds to a status change required in the device; comparing the temperature corrected Output signal with the defined condition and initiating the status change, if the temperature-corrected output signal satisfies the condition. On that way yourself in more reliable Way dependent From humidifying a device control, for example operate a display and / or switch a servomotor, etc.

In a further embodiment, the preceding method further comprises re-injecting the signal having the plurality of frequency components if the condition is not met. In this way, the moistening state of the sensor element can be temporally scanned in the desired manner or scan to the speci fected condition to cause a corresponding status change. On the basis of the determined temperature correction function, the triggering of the status change here is largely independent of the respective ambient temperature of the sensor element and thus enables a very precise triggering of the status change as a function of the moistening state. This is particularly important in applications in vehicles, aircraft, ships, etc., of great importance, since there very variable temperature conditions with very different humidifying conditions, such as fog, light snowfall, splashing, etc., occur, which is a very precise detection of the switch-on require for a windshield wiper system.

Consequently represents in advantageous embodiments the device is a controllable windshield wiper system whose status change corresponds to a wiping process, wherein the sensor element passed over becomes.

By the painting over or overflowing the Sensor element changes view so that in turn the moistening of the sensor element, so that in dependence the new moistening condition can in turn be decided whether the appropriate condition for a trigger the wiping process is given or not. This way you can in a very sensitive way the frequency the wiping operations be automatically adapted to the corresponding environmental conditions. In some embodiments can set the condition for the temperature corrected Output signal under the influence of the user take place, so the overall control process for the device to be controlled, for example, the windshield wiper system, in a very individual Way is customizable.

In In a further advantageous embodiment, the method comprises further determining a frequency component within the predefined ones Bandwidth for the signal to be fed in order to reduce its bandwidth. The Reducing the bandwidth of the signal, d. H. the selection of a few Frequencies or even a single frequency during certain phases of operation offers the possibility, to simplify the data acquisition, as possibly only an amplitude change the corresponding frequency components or the individual frequency component to take into account is. For example, during a certain phase the signal to be fed with the predefined Bandwidth are fed in order to obtain a "global" sample of the sensor state. Due to the global sensing of the sensor state, a or more suitable frequencies, for example resonance frequencies or nearby the resonances lying frequencies are selected, so for the further Observation of the moistening state within a certain time restrictions within which no significant temperature change of the sensor element or within other specified limits, the humidification condition determined on the basis of the few or individual frequency components becomes.

In a further embodiment The method further comprises after initiating the status change the device feeding the signal with reduced bandwidth, detecting a first response signal of the sensor element and using the response signal for generating a reference for a subsequent response signal.

On this way, a change of the state caused by the status change of the device may occur Humidification state of the sensor element used to a Reference for to generate subsequent sensor signals. For example, the status change a wiping operation of a windshield wiper system correspond, so that after the trigger This event, which is based on a control of the sensor element with a variety of frequencies according to the given Bandwidth based, so that the signal with reduced bandwidth, for example, a single frequency component is fed, its response signal a defined moistening state of the sensor element equivalent. For example, if the sensor element has been over-wiped the corresponding response signal obtained immediately thereafter a "dry" reference state be equated to the sensor element, so that from this Response signal distinguishing response signals as a change can be assessed in relation to this reference state. in this connection can be the assignment of a reference value for after the status change obtained response signal with the aid of the previously in the Sensor sampling with multi-frequency information obtained take place. For example, during the the sampling of the sensor element obtained with multiple frequencies Moistening state, which then led to the triggering of the wiper process, the Creation of the reference value immediately after the wiping process be used. For example, can be at a high initial Moistening during the sampling phase, for example, in a sudden splashing water humidification the windshield that was obtained after the first wiping process Reference value raised by the single frequency component accordingly be, since it can be assumed that the sensor element also immediately after the wiping process still has a certain degree of moisture.

In a further advantageous embodiment, the method comprises initiating a white teren state change of the device when a subsequent response signal in a predefined manner deviates from the reference and using a response signal after the re-initiation of the status change to generate an updated reference. In this way, for example, the wiping operation of the windscreen wiper can be used constantly for referencing a defined moistening state of the sensor element, so that a reliable operation results, wherein the sensor control and the signal evaluation are simplified. As described in the previous embodiment, also in this method, the information obtained during the sampling phase can be suitably used.

In In a further advantageous embodiment, the first response signal and / or the subsequent response signal and / or the response signal after the re-initiation represents the averages of a measurement event. In particular, the measurement process is based on a few Frequency components and in particular based on a single Frequency component carried out in a very rapid manner and can be evaluated, the possibility arises several individual To provide measurement results as averages, but still a high temporal resolution is possible.

In In a further advantageous embodiment, the method comprises detecting the status change the device and generating the reference in time correlated Way after detecting a status change. In this way it is possible to make changes the device for timing the generation of updated To use reference values. For example, the status change Represent a wiping operation of a windshield wiper, so that on reason the detection of the corresponding wiping operation, such as the wipe of the sensor element by the wiper blade, in a very precise manner a corresponding reference value can be generated. By detecting of the sweep The sensor element can thus immediately thereafter even with heavy rainfall a relatively well-defined "dryer" reference state be determined.

In In a further advantageous embodiment, the method comprises further defining an abort condition for the input of the signal with reduced bandwidth and feeding the signal with the multiple frequency components to produce an updated one temperature corrected output signal when the termination condition Fulfills is.

On This way can be efficient between a measurement phase Preservation of the temperature-corrected output signal and a measurement phase be switched with low bandwidth. In this case, the termination condition be dynamically variable or fixed, or several single conditions, dynamic or fixed, can be specified to a corresponding transition from the low bandwidth measurement phase to the scan measurement process to effect. For example, in case of a deviation of the constantly updated Reference values during of the low bandwidth measurement a new phase for recovery an updated temperature-corrected output signal causes be, since in this case could be a temperature drift. Further The termination condition may also include a time window, possibly in combination with other demolition conditions, so that in the To return to multiple frequencies. In other embodiments Can be done regularly during the Low bandwidth operation in the operation of generating the temperature corrected signal passed to make changes For example, to detect the wiper system. For example It can be snowfall or other conditions in bad condition the wiper blades possible be that with increasing duration an unacceptable moisture film remains on the disc or the sensor element, which then on reason the temperature-corrected output signal is visible and at generating multiple reference values during reduced bandwidth operation considered can be used to increase the wiper frequency accordingly.

Further Features, advantageous embodiments and advantages of the present invention will become apparent from the appended claims and the following detailed description of illustrative embodiments with reference to the following figures.

1a shows an exemplary temperature compensated humidification measuring system according to the present invention;

1b shows an embodiment with a sensor arrangement with a plurality of sensor areas;

1c shows by way of example a sensor element, wherein a plurality of relatively temperature-insensitive sensor areas are provided;

1d shows a very surface-efficient embodiment of the sensor element;

1e shows an embodiment in wel chem the sensor element is integrated in a laminated glass in a vehicle;

1f shows a measuring system according to an embodiment, wherein the sensor element is arranged in the windshield of a vehicle;

1g schematically shows an output signal of the sensor element according to the present invention;

1h graphically shows the temperature dependence of the dielectric constant of glass and PVB;

2 shows the course of a temperature-corrected output signal according to illustrative embodiments;

3a FIG. 10 is a flowchart of the procedure for controlling a windshield wiper system based on a temperature corrected output signal according to an illustrative embodiment; FIG.

3b shows a representative output during a fixed frequency phase where wiping events are detectable in the signal.

1a schematically shows a representation of a temperature-corrected humidification measuring system 150 in accordance with illustrative embodiments of the present invention. The measuring system 150 includes a sensor element 100 that has a first sensor area 110 and a second sensor area 120 having. The first sensor area has an inductive component 112 and / or a capacitive component 111 on, wherein in the illustrated embodiment, both components are provided and wherein substantially the capacitive component 111 by the temperature of the Sen sorbereichs 110 and is changeable by deposited at this area moisture. Similarly, the sensor area includes 120 an inductive component 122 and / or a capacitive component 121 , where again both components are provided and the capacitive component 121 much more affected by the temperature and precipitated moisture compared to the inductive component 122 is changeable. The sensor element 100 is designed to be the first sensor area 110 and the second sensor area 120 when exposed to the same moistening level, ie the same amount of liquid per unit area, and / or change at the same temperature with a change of the same in different ways. A corresponding behavior can be accomplished through structural measures, as described below with reference to the 1b to 1d is explained in more detail. The sensor element 100 is so relative to a drive device 160 arranged so that when operating the measuring system 150 a coupling for signal exchange between the drive device 160 and the sensor element 100 can take place. For example, a corresponding coupling can be made by a galvanic connection (not shown). In particularly advantageous embodiments, the drive device 160 designed so that an electromagnetic and in particular an inductive coupling to the sensor element 100 can be done. Furthermore, the drive device comprises 160 a controllable signal generator 161 which is designed such that a signal with a predetermined bandwidth, that is generated with a plurality of frequency components and via the drive means 160 in the sensor element 100 can be fed. The controllable signal generator 161 For example, it can be provided in the form of a voltage-controlled oscillator which, by means of a control voltage V _{C, supplies} a corresponding frequency component to the control device 160 outputs. With this arrangement, different frequency components within the desired bandwidth into the sensor element can be arranged in chronological order 100 be fed. It should be emphasized here that a drive signal having a plurality of frequency components within a specified bandwidth is considered to be a signal containing the various frequency components or ranges thereof sequentially or simultaneously. For example, the signal generator 161 be formed in the pulse generator, so that the sensor element 100 can be excited simultaneously with a variety of different frequency components. Furthermore, the measuring system includes 150 a temperature compensation device 140 , which is formed, one for the sensor state of the sensor element 100 to capture representative signal and as a temperature-corrected output signal 141 a corresponding processing instruction for converting the signal representative of the sensor state in the temperature-corrected output signal 141 in the temperature compensation device 140 implemented by software and / or hardware components. For example, in the temperature compensation device 140 corresponding values of response signals of the sensor element 100 be stored for a variety of different temperatures and for a variety of different Befeuchtungszustände, with corresponding value pairs a corresponding humidification representing the output signal 141 associated with lower temperature dependence than is the case for uncorrected sensor signals. In other embodiments, corresponding computational rules or other suitable means, such as calibration curves, and the like may be included in the device 140 be stored in order to use the temperature-corrected output signal 141 to obtain. In advantageous embodiments, the temperature compensation device 140 a measured value recording device 142 on, from the the control device 160 supplied signal can determine the signal corresponding to the uncompensated sensor state. For example, that of the drive device 160 supplied power, the change of the impedance of the drive means 160 and the sensor element 100 formed system, phase changes of the drive signal, etc. are detected by means of the measured value recording device.

1b schematically shows the sensor element 100 according to an illustrative embodiment, wherein the sensor element is a dielectric substrate 101 that is in the first area 110 and in the second area 120 can differ, so that there is a different behavior with temperature change and / or humidification state change due to the diversity of the dielectric material. In other embodiments, the structure of the substrate 101 in the first area and in the second area 110 . 120 be essentially identical. The substrate 101 may be any suitable substrate material to or on a conductive pattern 130 manufacture. In advantageous embodiments, the substrate is 101 provided as a planar substrate whose lateral dimensions, as the length 101l and as width 101b are each shown significantly larger than its thickness, ie the dimension in the direction perpendicular to the plane, as later also from 1f is apparent. The substrate 101 can advantageously, at least in regions, be constructed of an optically transparent material, so that in particular when using the measuring system 150 As a rain sensor in windscreens advantageously no appreciable functional limitations. However, in other embodiments, the optical transparency of the substrate is 101 not required or not desirable and the substrate 101 may be completely or partially opaque. The first and the second area 110 and 120 are designed so that they have a different behavior when humidifying or a different behavior with temperature change. The behavior of the sensor element 100 among other things, is determined by the ladder structure 130 and determined in particular by their geometric arrangement. For example, the frequency behavior of the first and the second region, which depends on the geometric arrangement to each other, dhua of the distance 101 to each other, as weak or non-coupled oscillating circuits or as coupled oscillating circuits can be considered, the value of the respective inductive component 112 . 122 and capacitive component 111 . 121 dependent, wherein for the uncoupled case for both sensor ranges a resonance frequency of f = 1 / 2π√ LC results. In the illustrated embodiment, the conductor structure 130 a first structure 131 for the first sensor area 110 as well as a second structure 132 for the second sensor area 120 on. In the example shown, a different behavior of the two sensor areas is achieved by the structure 132 is constructed of a single continuous conductor having a plurality of adjacent conductor sections over the entire second sensor region, so that overall a relatively small parasitic capacitance results. Furthermore, this also gives a large available sensor area, which in the case of local moistening leads to a noticeable change in the total capacitance of the second sensor area 120 leads. In the illustrated embodiment, the structure of the first conductor structure differs 131 from the structure of the ladder structure 132 in that adjacent conductor track sections are provided with a smaller distance and a smaller number, so that a relatively large area of the first conductor pattern 131 which results in little or no change in parasitic capacitance upon humidification of this trapped region. Nevertheless, the parasitic capacitance of the conductor structure 131 is greater than that of the structure 132 , Due to the large enclosed area, which shows little effect when moistened, results in a relatively small inductance, so that the corresponding resonance frequencies of the sensor areas 110 and 120 may have a similar value. In the illustrated embodiment also results for the sensor area 110 due to the relatively large parasitic capacitance in the region of the strip conductors due to their small distance corresponding to a small proportionate change in humidification of the sensor area 110 above the ladder structure 131 , ie the sensitivity during humidification is relatively low. Furthermore, due to the small areas, which leads to a change in capacitance when humidified, ie essentially the area of the conductor structure 131 is taken, in combination with the lower sensitivity, a significantly lower overall dependence of the frequency behavior of the moistening, for example, the location of the resonance frequency of the first area 110 compared to the second area 120 , For example, at a predetermined degree of moistening of the sensor element 100 That is, for a given amount of moisture per unit area, for the sensor area 120 up to a hundred times or more higher sensitivity can be achieved, the temperature behavior of the two sensor areas 110 and 120 can be very similar, especially if in both sensor areas, a dielectric material is used with the same temperature behavior.

1h shows qualitatively the temperature ver hold typical dielectric materials used in the automotive industry. Curve A in 1h shows the temperature behavior of the permittivity of glass, while curve B expresses the corresponding behavior of PVB. This shows that a sensor element having only a very small frequency dependency for humidification but containing in its structure a material with a large permittivity change with temperature change can be used very efficiently as a temperature reference, especially if there is sufficient thermal coupling to a region is present, which shows a high sensitivity for a corresponding change in the moistening state. In the in 1b This embodiment is illustrated by the specific geometric design of the first area 110 reached. Furthermore, the efficiency of the temperature correction can be further improved by, for example, in the second regions 120 a dielectric material with a lower temperature dependence is used.

1c shows the sensor element 100 according to another illustrative embodiment, in which a plurality of first regions 110 are provided, which have a relatively low sensitivity for humidification, as previously with reference to 1b is explained. In particular, in these embodiments, the distance of the individual first areas 110 from the moistening sensitive area 120 be chosen so that still a relatively uncoupled arrangement arises, but due to the geometric distribution of the first areas 110 a very representative measure of the temperature even at the location of the sensor 120 can be obtained. For example, a very local temperature change in the sensor element 100 due to the corresponding changes of the individual elements 110 recorded better and thus a more accurate temperature correction can be achieved.

1d schematically shows a plan view of the sensor element 100 according to further embodiments, wherein herein a particularly surface-efficient embodiment is shown. In this arrangement, the first area 110 with the first structure 131 arranged so that these are the second areas 120 with the second conductor structure 132 essentially encloses. Due to this geometric configuration results in a relatively high coupling of the two resonant circuits in the areas 110 and 120 , again the first area 110 only very slightly when humidifying the sensor element 100 is influenced in his behavior. To a corresponding temperature-corrected statement about the humidification state of the sensor element 100 To obtain, it is advantageous to make the first region and the second region so that they have a different behavior with temperature change. This can be achieved, for example, that in the first area 110 a material with a different behavior of the permittivity compared to the second region 120 is introduced. This can be advantageous if, for mechanical reasons, for example with regard to the mechanical behavior or the fracture behavior, the essential surface portion of the sensor element 100 has to meet certain conditions, for example when the sensor element 100 a part of a laminated glass pane. Because this is only small amounts of another material in the first area 110 can be introduced, thus the mechanical behavior of the sensor element 100 be maintained to a high degree. If a particularly different temperature behavior of the two areas 110 and 120 is required, a dielectric material with a negative temperature response can also be used.

In this way, the sensor element 100 be integrated into, for example, a pane of glass without great functional impairment.

1e shows a typical application example, wherein the sensor element 100 with a substrate 101 is provided, which forms part of a laminated glass pane, such as is used in vehicles. Here, the substrate comprises 101 a first glass pane 102 , which typically has a thickness of about 2.1 mm, followed by a layer 103 made of PVB with a typical thickness of about 0.76 mm. Above it is a glass pane 104 arranged with a typical thickness of about 2.1 mm, being between the PVB layer 103 and the second glass pane 104 the ladder structure 130 , possibly in conjunction with a carrier material. The ladder structure 130 can be printed on a thin film or can by Kle advertising, etc. on the second glass 104 be applied before the structure of the layers 102 . 103 and 104 is joined together by pressure and heat.

1f shows a typical positioning of the sensor element 100 in the area of a windshield 182 , wherein the sensor element 100 within the wiper area 180 at least one windscreen wiper is arranged. The other components of the measuring system according to the invention 150 can in this case, for example, in the rearview mirror 181 or at another suitable location. In particular, the measuring device has a corresponding control device 190 on that a communication of the measuring system 150 with a peripheral device, such as a drive circuit for the windshield wiper system allows.

For the operation of the measuring system 150 will first be one in the temperature compensation direction 140 implemented temperature correction function determined. For further explanation, for example, refer to the embodiment of the sensor element 100 referenced as it is in 1b is shown. The areas 110 and 120 can be understood as temperature and humidity-dependent oscillatory circuits which are electromagnetically relatively decoupled in the embodiment mentioned above. Because of the training of the first area 110 out 1b These areas have a very low sensitivity when humidifying the sensor element 100 shows, its change in the resonance frequency due to a change in the capacitive component 111 essentially due to temperature influences. In contrast, the second area points 120 if it is constructed with the same dielectric materials as the area 110 , a similar temperature behavior, with in addition a high sensitivity at humidification of the sensor element 100 given is.

1g shows qualitatively the frequency-dependent behavior of the areas 110 and 120 at a temperature change. In 1g the illustrated curve shows one for the sensor state of the element 100 representative value, for example, the impedance of the drive circuit 160 and the sensor element 100 formed coupled system, in which case due to the relative decoupling of the two areas 110 and 120 two relatively independent resonant frequencies f1 and f2 through the respective capacitive and inductive components 111 . 121 and 112 and 122 are defined. Here, the resonance frequency f1 is for the substantially temperature-sensitive region 110 (TS) due to structural measures greater than a corresponding resonant frequency f2 of the second range 120 (RS). Because of the similar temperature behavior, both regions show a decrease in their respective resonant frequencies f1, f2 as the temperature increases, as indicated by the corresponding arrows. 1g describes this situation for a predefined humidification state of the sensor element 100 which may be defined, for example, as a dry state. Before the actual measuring operation of the measuring system 150 can therefore first the temperature behavior of the sensor element 100 ie the two areas 110 and 120 can be determined by for a predefined humidification state of the sensor element 100 the frequency behavior is determined. In this case, it may be advantageous to obtain current measured values for the resonance frequencies f1 and f2 or for other values representing these resonance frequencies for several temperatures. For example, the sensor element 100 are heated or cooled starting from a certain temperature, wherein the corresponding resonance curves are determined at several times. If a corresponding determination of the temperature behavior is not suitable, for example due to mass production, etc., can in the temperature compensation device 140 a corresponding model can be implemented, from which the temperature behavior in the entire temperature range of interest is determined from the corresponding resonance frequencies at a temperature. For this purpose, for example, the data used in 1h are shown. Based on the determined temperature behavior of the sensor element 100 Then, a temperature correction function can be determined, for example by "normalizing" the behavior of the resonance frequency f2 to the corresponding behavior of the resonance frequency f1, so that a corresponding deviation from this normalization additionally influences the capacitive components of the range 120 indicates due to moistening. The signal deviating from the normalization can then be used as the temperature-corrected output signal 141 be issued. The creation of the temperature correction function can be done before the actual operation of the measuring system 150 be executed, for example, when manufacturing the measuring system 150 in its assembly, for example in a vehicle, and the like. Furthermore, the temperature correction function may additionally or alternatively during the operation of the measuring system 150 be created or updated. Depending on manufacturing tolerances, it may be sufficient to use the temperature correction function for a particular type of sensor element 100 and then create these for a variety of sensor elements 100 to use. With increased precision of the temperature correction or the occurrence of possible manufacturing tolerances, the determination of the temperature correction function can be performed individually as needed. Furthermore, it is in determining the temperature behavior of the sensor element 100 in some embodiments, it is not necessary to detect the temperature absolutely, but it is only sufficient to have a certain temperature change, but that over the sensor element 100 to be as homogeneous as possible, with corresponding values being recorded several times corresponding to the respective resonance frequencies f1 and f2. For temperature ranges for which there are no values for the determination of the temperature behavior and which are nevertheless in the practical operation of the measuring system 150 can occur, then a corresponding extrapolations can be carried out to still achieve a relatively reliable temperature correction.

In further embodiments, two or more metrics may be derived from the response signal of the sensor element 100 be determined from which then determine a corresponding disturbance, for example, the temperature dependence of the response signal and thus compensate. at For example, from the response of the impedance of the sensor element 100 and the drive circuit 160 formed coupled system and the phase angle of the response signal can be determined. From these results, the real part and the imaginary part of the response signal can then be calculated, which can then be used for temperature compensation due to the different temperature behavior.

In embodiments in which there is no such pronounced independence of the two sensor regions in the electrical behavior and / or in which the temperature behavior of the two sensor regions and / or the behavior during humidification is different but not so much decoupled, that is, even if moistening of the sensor element 100 a certain measurable change in the frequency response of the first sensor area 110 may be advantageous, it may be advantageous to carry out the determination of the temperature behavior for conditions corresponding to different Befeuchtungszustände. For example, reproducible "humidity conditions" on the sensor element 100 be prepared by layers of a dielectric material on the sensor element 100 For example, a material with an ε comparable to water in different layer thicknesses can be applied, or layers with integrated "drops" of different densities can be applied and the like. For example, a sensor prepared with a corresponding "moistening condition" 100 From the resulting data, at least in a certain range, an assignment of value pairs can take place such that for certain value pairs f1, f2 a corresponding moistening state can be detected essentially independent of the temperature.

2 For example, schematically shows a temperature reference function A, which can be considered as the "threshold" of a temperature correction function, in which case the first areas 110 and the second area 120 have a substantially similar temperature behavior. The function A represents the course for a resonance frequency f2 of the second range normalized to the resonance frequency f1, ie temperature-compensated 120 In the case of pairs of values (f1, f2), which lie on the curve A, there is a moistening state of the sensor element 100 which corresponds to the reference moistening state, ie, the dry state. In a deviation from the curve A in the hatched area, ie when the natural frequency f2 of the second sensor area 120 is reduced more by additional humidification than corresponds to the reduction of the natural resonance f1 due to a change in temperature, thus becomes a state of moisture on the sensor element 100 displayed. Thus, points, ie pairs of values (f1, f2), which lie on the curve A or in the hatched area represent the normal behavior of the measuring system 150 in drought or rain, while a deviation above the curve A indicates an intrinsic change. In this case, an update of the temperature correction function may be initiated, or corresponding correction parameters may have previously been determined to determine the behavior of the measurement system 150 return to the calibrated area. Possibly. Corresponding correction parameters can also be an indication of the status of the measuring system 150 convey. For example, a systematic deviation from the curve A upwards may indicate the aging of one or more components.

During the actual measuring operation of the system 150 , which was preceded by the determination of the temperature correction function immediately and / or a long time ago, by means of the control device 160 and the controllable signal generator 161 a drive signal of suitable bandwidth, the at least the natural frequencies f1 and f2 for one for the operation of the measuring system 150 to include the expected temperature range, in the sensor element 100 fed. For example, the drive signal may initially be provided with some frequency components that span a further frequency range in order to reliably include the corresponding resonance frequencies. On the basis of this coarse fixation of the corresponding resonance frequencies, the temperature compensation circuit can then be used 140 the controllable signal generator 161 trigger so that the bandwidth is reduced to the required bandwidth for detecting the corresponding resonant frequencies in order to determine if necessary, the corresponding resonant frequencies with higher accuracy. On the basis of the obtained data, ie the resonance frequencies or equivalent values, the temperature-corrected output signal can then be determined by means of the temperature correction function 141 to be provided.

The temperature corrected output signal 141 can then be used for further control tasks, for example, to initiate a change in state of a device to be controlled, which may represent a windshield wiper system of a means of transport in a particular embodiment. To maintain a high degree of precision in the control of the windshield wiper system or other device, the Steue consistently on the basis of the temperature-corrected output signal 141 respectively. In this case, the temperature compensation device 140 together with the measuring device 142 preferably designed so that the output signal 141 Herein, in some embodiments, the drive signal may be provided such that the frequency range of interest is simultaneously input to the sensor element 100 is fed, so that with appropriate training of the device 142 the frequency response of the sensor element 100 can be obtained within a short time intervals. For this purpose, the temperature compensation device 140 Advantageously, corresponding means, for example a device for fast Fourier transformation and the like, so that an efficient evaluation of the frequency response of the sensor element 100 is possible. In other embodiments, in which the for sensing the sensor element 100 required frequency components are sequentially fed, suitable integrated circuits can be used which enable scanning over a predetermined bandwidth in a rapid and reliable manner.

In other advantageous embodiments, a simplified measuring procedure can be carried out during certain measuring phases, wherein a temperature correction is avoided. In these cases, the signal to be injected can be significantly reduced in bandwidth so that only a few frequency components or a single frequency may be sufficient to match the humidification state of the sensor element 100 to determine with sufficient accuracy. Additionally, in some embodiments, additional information may be used for reference value formation during a reduced bandwidth measurement phase. In the case of driving a windshield wiper system, this additional information for referencing from the wiper event when sweeping the sensor element 100 be won.

In reference to 3a and 3b an exemplary embodiment is described in which a change between a measurement phase with a large bandwidth for generating a temperature-corrected output signal and a measurement phase with a drive signal of low bandwidth is alternated, wherein additionally referencing information is obtained by the control of the windshield wiper system.

3a shows a flowchart of a corresponding operation 300 according to illustrative embodiments using a measuring system, such as the system 150 , In step 301 the temperature behavior of the sensor element and a corresponding temperature correction function (TKF) is determined. The determination of the temperature behavior and the temperature correction function can be carried out in the manner described above. In step 302 the measurement takes place in the scanning mode, ie the drive signal is transmitted to the sensor element with a correspondingly large bandwidth 100 and based on the frequency response of the sensor element 100 becomes the temperature corrected output signal 141 generated. In a decision block 303 , which may be provided in some embodiments, it is decided whether an update of the temperature correction function is required. The decision may be made on the basis of predetermined criteria such as those enumerated above. For example, a deviation of the temperature-corrected output signal indicating a non-permitted system status may be used as a decision criterion after applying the temperature function. If the condition for updating the temperature correction function is satisfied, the flow jumps to the step 301 back. It should also be mentioned that a corresponding update can be initiated by the user. If the decision criterion in the step is not fulfilled 303 the process goes to the step 304 or, in some embodiments, the method goes directly from the step 302 to the step 304 further. In the decision block 304 is a condition for a change in status of a device to be controlled set up, which in the present case, for example, the threshold value for the degree of humidification of the sensor element 100 can represent. The temperature corrected output signal 141 thus represents the degree of wetting of the sensor element 100 and a suitably selected threshold for turning on the windshield wiper system may be implemented or adjusted. If the status change condition is not met, the process flow returns to the step 302 back, so that a new value for the temperature-corrected output signal is measured. If in the block 304 the condition is met, in some embodiments, a drive of the device, ie the windshield wiper can be initiated. Thereafter, in these embodiments, the step may again 302 be returned, if a measurement with high precision compared to temperature effects is still desired. In other cases, the process flow can then become a decision block 306 continue in other cases immediately after the block 304 can be jumped if the condition for the status change is fulfilled. In the decision block 306 a decision is made as to whether operation with reduced bandwidth is desired. In particular, in this case an operation with a single frequency component take place, so that due to the simpler control and signal evaluation, a faster Datenennahme to assess the humidification state of the sensor element 100 can be performed. If in the decision block 306 is decided that no operation with reduced bandwidth is required, the process flow returns to the step 302 back. If reduced bandwidth operation is desired, the process flow goes to step 307 further. In step 307 one or more suitable frequencies are selected for operation at reduced bandwidth. For this purpose, for example, the signal that during the measurement in the sampling mode in step 302 is obtained, are processed so that a frequency can be determined, in which a large amplitude change is to be expected when changing the humidifying condition. For example, with a signal the form may look 1g rich for the second Sensorbe 120 determining a frequency in which the greatest possible or maximum change of the amplitude results with a change of the frequency. For example, the frequency is approximately halfway between the local maximum and the local minimum of the location RS 120 a suitable frequency.

In step 308 then with the one or more in the step 307 measured at selected frequencies. For this purpose, the controllable signal generator 161 be driven accordingly, so that a signal at the selected frequency or from the selected frequencies in the sensor element 100 is fed. Further, also in the steps 307 or 308 a control of the device to be controlled take place, if not already in the step 305 took place. For example, in a time-correlated manner, the measurement can take place at the fixed frequency after the activation of the windscreen wiper. Then in the step 309 generates a reference value that can be used for further measurement at a fixed frequency. For example, the signal amplitude, the immediately after over-wiping of the sensor element 100 is detected as a measure of a Referenzbefeuchtungszustand be evaluated. Thereafter, the process flow goes to the decision block 310 Next, in which is decided on the basis of a dynamic or fixed predetermined termination condition, whether the measurement process should be continued with the fixed frequency or not. If the abort condition is met, the process flow jumps to the step 302 back, while if the termination condition is not met, measuring with the fixed frequency in step 308 is continued. Because of compared to the step 302 The measurement performed in the sampling mode can loop out the steps 308 . 309 and 310 be carried out very quickly, so that a corresponding averaging and thus lower fluctuations of the measured values and the reference values can be achieved. In step 309 For generating a reference value for this measurement loop, further information can also be used for the referencing.

3b schematically shows, for example, the signal amplitude when the process flow in the loop 308 . 309 and 310 is located, wherein in one of these steps can be done to control the windscreen wiper. In 3b 5 signal sections A, B, C, D and E are shown. The signal sections identify the magnitude of the signal amplitude at a fed fixed frequency for the sensor element 100 , As stated previously, the presence of moisture on the second sensor area causes 120 a reduction of the corresponding resonant frequency, which results in a reduction of the signal amplitude, as for example in the range RS 120 in 1g is apparent. Thus, the relatively low signal value in region A indicates that there is a relatively high level of humidification on the sensor element 100 prevails. As a result of the comparison with a corresponding threshold, it then becomes one of the steps 308 . 309 or 310 decided that the windshield wiper is to be operated, whereupon when sweeping the sensor element 100 a corresponding relatively abrupt change of the frequency response results, which leads to the clearly recognizable signal section D. After a single over wipe of the sensor element 100 the moisture is essentially from the sensor element 100 removed, so that there is a corresponding increase in the signal amplitude in the area B. The renewed sweep of the sensor element 100 during the return movement of the windscreen wiper results in a correspondingly significant change in the signal amplitude in section E, after which the sensor element 100 remains substantially free of moisture. Since the signal sections D and E are clearly recognizable, these events can be generated when the reference value is generated in step 309 be used, for example, immediately after such an event of a relatively well-defined humidification state of the sensor element 100 is to go out. Thus, for example, the signal amplitude in section B immediately after section D and / or the signal amplitude of section C immediately after section E may be used as the reference value. So if in the further course of the measurement in the loop 308 . 309 and 310 a corresponding reference value is fallen below in a predetermined manner, thus can again be a control of the windshield wiper. Of course, other information, such as the latest temperature-corrected output signal, in step 303 be included for referencing on the basis of wiper events.

Claims (44)

Temperature compensated humidification measuring system With: a sensor element with a mounted on a substrate Conductor structure, which is an inductive component and / or capacitive Component, wherein the substrate has a first sensor area and a second sensor area that at a predefined temperature change and / or a predefined change in the humidification state each different to the change the inductive component and / or each different from the change contribute to the capacitive component, one with the sensor element coupled drive device, which is formed, a signal with several, a frequency range with a first bandwidth to feed defining frequency components into the sensor element, and one with the drive device and / or the sensor element coupled temperature compensation device formed is, based on the different behavior with temperature change and / or change the humidifying state of the first and second sensor area a the Moisture state of the first and / or second sensor area corresponding provide temperature corrected output signal. Temperature compensated humidification measuring system according to Claim 1, wherein the conductor structure is substantially planar Arrangement executed is, so that dimensions in the lateral direction of the conductor structure are much larger as a dimension perpendicular to the lateral direction. Temperature compensated humidification measuring system according to Claim 1 or 2, wherein the first and the second sensor area are formed, the value of the capacitive component with temperature change and / or change the humidification condition stronger to change as the value of the inductive component. Temperature compensated humidification measuring system according to at least one of claims 1 to 3, wherein the first sensor area with a first dielectric a first temperature response of its relative permittivity and the second sensor area a second dielectric with a second, from the first temperature transition different temperature course of his relative permittivity having. Temperature compensated humidification measuring system according to Claim 1 or 2, wherein the first and the second sensor area are formed, the value of the inductive component with temperature change and / or change the humidification condition stronger to change as the value of the capacitive component. Temperature compensated humidification measuring system according to at least one of claims 1 to 5, with the same humidification per unit area of first and second sensor area, the second sensor area a shows less influence on the capacitive and / or inductive component as the first sensor area. Temperature compensated humidification measuring system according to Claim 6, wherein one wettable by moisture and the capacitive and / or inductive component influencing sensor surface in the second Sensor area is smaller than in the first sensor area. Temperature compensated humidification measuring system according to at least one of claims 1 to 7, wherein at the same temperature change of the first and second Sensor area, the first sensor area less influence the capacitive and / or inductive component shows as the second Sensor area. Temperature compensated humidification measuring system according to one of the claims 1 to 8, wherein the conductor pattern is formed so that through the Ladder structure a resonant circuit is formed with a first and a second determined by the inductive and capacitive component Resonance frequency. Temperature compensated humidification measuring system according to at least one of claims 1 to 9, wherein the conductor structure has a first structure and a second structure Structure, which are galvanically decoupled from each other. Temperature compensated humidification measuring system according to Claim 10, wherein the first structure and the second structure laterally are arranged side by side. Temperature compensated humidification measuring system according to Claim 10 or 11, wherein the second structure is the first structure encloses laterally. Temperature compensated humidification measuring system according to Claim 12, wherein a distance of adjacent conductor sections of second structure is smaller than a distance of adjacent conductor sections the first structure. Temperature compensated humidification measuring system according to at least one of claims 10 to 13, with the first structure of a single contiguous first conductor and the second structure of a single contiguous second conductors are constructed. Temperature compensated humidification measuring system according to Claim 14, wherein the first and second conductors are parallel or have concentric sections. Temperature compensated humidification measuring system according to Claim 15, wherein the length of the first conductor is larger as the length of the second conductor. Temperature compensated humidification measuring system according to at least one of claims 1 to 16, wherein the substrate is at least partially transparent. Temperature compensated humidification measuring system according to Claim 17, wherein the substrate represents a part of a glass sheet. Temperature compensated humidification measuring system according to Claim 18, wherein the glass pane is formed as a laminated glass pane and, as an intermediate layer, an amorphous thermoplastic material comprising in the first and / or second sensor area is. Temperature compensated humidification measuring system according to Claim 18 or 19, wherein the glass pane installed in a vehicle is. Temperature compensated humidification measuring system according to at least one of claims 1 to 20, wherein the sensor element and the drive device galvanic are decoupled. Temperature compensated humidification measuring system according to at least one of claims 1 to 21, wherein the sensor element and the temperature compensation device are galvanically decoupled. Temperature compensated humidification measuring system according to one of the claims 1 to 22, wherein the temperature compensation device is formed is the multiple frequency components sequentially in the sensor element feed. Temperature compensated humidification measuring system according to one of the claims 1 to 23, wherein the drive device is formed, a signal the multiple frequency components in the sensor element simultaneously feed. Temperature compensated humidification measuring system according to one of the claims 1 to 24, wherein the drive device is designed, a signal with a second bandwidth that is smaller than the first bandwidth is to feed into the sensor element. Temperature compensated humidification measuring system according to one of the claims 1 to 25, further comprising a control device formed is to receive the temperature corrected output signal and on its basis is a status change effect a device coupled to the control device. Temperature compensated humidification measuring system according to Claim 26, wherein the device is a windshield wiper system. Method for generating a moistening condition a sensor element having a first and a different behave second sensor area with one each of humidification and temperature dependent by a conductor structure produced inductive component and / or capacitive component, dependent output signal, wherein the method comprises the steps of: Determining a temperature behavior of the first and second sensor areas at a predefined one Humidification degree corresponding sensor state of the first and second Sensor area in response to a feed of a drive signal with a given bandwidth, Determining a temperature correction function based on the temperature behavior, the temperature correction function at least for the sensor state corresponding to the predefined degree of humidification a decrease in the temperature dependence of the output signal results and Use the temperature correction function to generate a temperature-corrected output signal of the sensor element and / or a further sensor element of the same construction based on a Response of the first and second sensor area to an input Signal with several, within the given bandwidth lying Frequency components. The method of claim 28, wherein determining the Temperature behavior includes: Determining a first temperature behavior of the first sensor area at a first predefined one Moisture level corresponding sensor state of the first sensor area in response to the supply of a first drive signal with a first bandwidth, Determining a second temperature behavior of the second sensor area at a second predefined one Moisture level corresponding sensor state of the second sensor area in response to the supply of a second drive signal with a second bandwidth. The method of claim 28 and / or 29, further comprising determining a first resonant frequency and a second resonant frequency Resonance frequency. A method according to any one of claims 28 to 30, wherein the fed Signal fed without galvanic coupling in the first and second sensor area becomes. A method according to any one of claims 28 to 31, wherein one for moistening sensitive surface and / or a sensitivity for Humidification of the first sensor area is smaller than a corresponding one area and / or sensitivity of the second sensor region. The method of claim 29, wherein the first and the second predefined degree of humidification is the same. The method of claim 33, wherein the first and the second predefined moistening level is a reference moistening level in which no wetting with liquid of the sensor element is present. The method of any one of claims 28 to 34, further comprising: Determining the behavior of the sensor element at several sensor states, respectively correspond to a different degree of moistening. Method for controlling a device by means of a temperature corrected output signal, according to the method at least one of the claims 28-35, the method of controlling the device further comprises: Set a condition for the temperature corrected Output signal, the condition being a humidifying condition of the Corresponding sensor element that requires a change of state of the device, to compare the temperature-corrected output signal with the defined condition and Initiate the status change, if the temperature-corrected output signal meets the condition. The method of claim 36, further comprising: again Feeding in the signal with the several frequency components when the condition is not fulfilled is. The method of claim 37, wherein the device represents a controllable windshield wiper system whose status change corresponds to a wiping process, wherein the sensor element passed over becomes. The method of claim 38, further comprising: Determine a frequency component within the predefined bandwidth for the signal to be injected, the bandwidth of the signal to be fed to reduce. The method of claim 39, further comprising: after initiating the status change the device, feeding the signal with reduced bandwidth, Detecting a first response signal of the sensor element and using the first response signal for generating a reference for a subsequent one Response signal. The method of claim 40, further comprising: Initiate another status change the device when a subsequent response signal in predefined Way different from the reference and using a response signal after re-initiating the status change to generate a updated reference. Method according to one of claims 40 and / or 41, wherein the first response signal and / or the subsequent response signal and / or the response signal after re-initiation as averages represents individual measurement events are. The method of any of claims 40 to 42, further comprising: Detecting the status change the device and generating the reference in time correlated Way after detecting a status change. The method of any one of claims 40 to 43, further comprising: Defining a termination condition for injecting the signal with reduced bandwidth and feeding the signal with the multiple Frequency components for generating an updated temperature corrected Output signal when the termination condition is met.