KR102454594B1 - Rain sensor detecting vibration and method of operation thereof - Google Patents

Abstract

Disclosed are a rain sensor for sensing vibration and an operation method thereof. According to an embodiment of the present invention, the rain sensor for sensing vibration receives a first electric signal having a first resonance frequency from a first resonance circuit connected to a sensing coil arranged to face a sensing member and be separated from the sensing member in a first direction. The rain sensor for sensing vibration receives a second electric signal having a second resonance frequency from a second resonance circuit. The rain sensor for sensing vibration generates a third electric signal having a differential frequency component corresponding to the difference between the first resonance frequency and the second resonance frequency by processing the first electric signal and the second electric signal. The rain sensor for sensing vibration also generates an output signal having the size corresponding to displacement in a first direction of the sensing member on the sensing coil and having the size corresponding to the differential frequency component. The purpose of the present invention is to provide the rain sensor and the operation method thereof, capable of accurately dividing contact of a raindrop and a change in humidity caused by dew, fog, or frost without an additional sensing unit.

Description

A raindrop sensor that detects vibration and its operation method {RAIN SENSOR DETECTING VIBRATION AND METHOD OF OPERATION THEREOF}

The present invention relates to a rain sensor and an operating method thereof, and specifically, a rain sensor capable of distinguishing between dew or frost and rain without requiring additional means for removing moisture, and an operating method thereof is about

In general, a rain sensor mounted on a vehicle measures the amount of rainwater by detecting raindrops (raindrops) in contact with a windshield of the vehicle. Rain sensors include light-based rain sensors, capacitive-based rain sensors, acoustic-based rain sensors, and camera-based rain sensors.

The light-based rain sensor measures the amount of rainwater by measuring the light signal reflected by raindrops using an infrared sensor. The light-based rain sensor may misjudge the change in refraction of light caused by objects other than raindrops as raindrops, may malfunction due to sensitivity to external light, and has a small sensing area.

The capacitive-based rain sensor senses the amount of raindrops formed on the windshield by measuring changes in capacitance and/or resistance that occur when raindrops exist between electrode patterns. The capacitive sensor has a structure embedded between multilayer boards, and is difficult to manufacture due to problems with electrical wiring and the like, and is somewhat expensive. The capacitive sensor detects the proximity of an object having a specific permittivity, and since it is affected not only by the proximity of raindrops, but also by the amount of moisture or humidity, there is also a problem in responding to dew or frost. For this reason, in a rain sensor using a capacitive sensor, a method of removing moisture by attaching a heating element together is used, which causes a problem in that the cost increases.

The acoustic-based rain sensor measures the amount of raindrops by sensing the sound pressure signal generated when the raindrops contact the windshield with a microphone. Acoustic-based rain sensors require a filter for specific frequency selection to remove noise signals in the vehicle.

The camera-based rain sensor measures the amount of raindrops by analyzing the frequency pattern caused by voltage emission when raindrops are present on pixels in a complementary metal oxide semi-conductor (CMOS) pixel sensor. The camera-based rain sensor has disadvantages in that the sensitivity for distinguishing between previously fallen raindrops and later fallen raindrops, that is, the measurement sensitivity is low, the sensing area of the optical sensor is partial and cannot distinguish objects other than raindrops, such as dust, leaves, and the like.

Prior Document 1, Korean Patent Application Laid-Open No. KR 10-2021-0015194 "Rain sensor for vehicle, wiper system and wiper control method using the same" discloses a prior art using both a sensor for detecting a change in capacitance and an acoustic sensor. Prior Document 1 determines the size of adjacent raindrops based on the change in capacitance, but it is difficult to determine whether the raindrops actually contacted because they are affected by changes in humidity such as dew or frost. Therefore, in Prior Document 1, an embodiment in which an acoustic sensor is added in order to determine whether raindrops actually contacted is disclosed. The addition of such an acoustic sensor results in an increase in cost.

Korean Patent No. KR 10-2327610 "Rain sensor and wiper driving device including same", which is Prior Document 2, forms a reaction layer made of a carbon micro coil (CMC) material on a substrate, and is formed on the substrate, but the reaction layer An impedance change between a pair of sensing electrodes embedded therein is detected. Even in Prior Document 2, since the impedance change between a pair of sensing electrodes disposed on the same plane on the substrate is sensitively affected by the change in capacitance, the change in humidity caused by dew or frost and raindrops actually come into contact with each other. The problem remains that it is difficult to accurately distinguish between

Therefore, there is a growing demand for a raindrop sensor (rain sensor) that can accurately distinguish whether raindrops are actually in contact with an increase in humidity caused by dew or frost without an increase in cost.

Korean Patent Laid-Open Patent KR 10-2021-0015194 "Rain sensor for vehicle, wiper system and wiper control method using the same" (published on February 10, 2021) Korean Patent Registration KR 10-2327610 "Rain sensor and wiper driving device including the same" (published on November 11, 2021)

The present invention has been derived to solve the problems in the prior art, and a raindrop sensor capable of accurately distinguishing contact of raindrops from changes in humidity caused by dew, fog or frost without additional sensing means and an operating method thereof aims to propose

The present invention detects the displacement of the sensing member in the first direction due to the force applied in the first direction perpendicular to the substrate by inductive coupling with the sensing coil, and through this, regardless of the change in the amount of moisture or humidity, An object of the present invention is to propose a raindrop sensor capable of detecting contact presence and an operation method thereof.

Since the raindrop sensor of the present invention does not require a configuration for varying the frequency of an input electrical signal, it is an object of the present invention to reduce power consumption. In addition, by detecting a minute shift of the resonant frequency, it is possible to sense vibration caused by contact of raindrops, and the purpose is to increase the sensitivity to vibration.

The raindrop sensor of the present invention may be used alone, or even when used together with other known sensing means, the purpose of the present invention is to increase the effect due to the combination thereof. The raindrop sensor of the present invention can provide unique information that does not overlap with information provided by other sensing means, and when combined with other sensing means, is also efficient in that it can provide comprehensive information on weather conditions. .

In addition, since the capacitive raindrop sensor of the prior art can detect a change in dielectric constant only when raindrops contact the periphery of the sensor, the location where the raindrop sensor is installed must be considered very carefully. Also, for the same reason, when it rains lightly, it is difficult to accurately detect the situation, and only the size of the raindrops in contact with the sensor can be detected in detecting the size of the raindrops, so the accuracy is significantly lowered. This problem is fundamentally difficult to solve even if an acoustic sensor and an optical sensor are used together or a special material is used as in the prior literature.

However, since the present invention can directly detect the magnitude of the vibration of an object on which the sensor is installed, there is no restriction on the location where the sensor is installed. In this case, it is possible to comprehensively determine using the magnitude and frequency of vibration, providing much more accurate information.

The present invention is a configuration derived to achieve the above object, and the vibration sensing raindrop sensor according to an embodiment of the present invention is spaced apart from the sensing member in a first direction and connected to a sensing coil disposed to face the sensing member. Receive a first electrical signal having a first resonant frequency from a first resonant circuit, receive a second electrical signal having a second resonant frequency from a second resonant circuit, and signal processing for the first electrical signal and the second electrical signal to generate a third electrical signal having a differential frequency component corresponding to the difference between the first resonant frequency and the second resonant frequency, and having a magnitude corresponding to the differential frequency component in the first direction of the sensing member with respect to the sensing coil An output signal having a magnitude that is formed to correspond to the displacement is generated.

The rain drop sensor may include a readout circuit that receives the first electrical signal and the second electrical signal, generates a third electrical signal, and generates an output signal.

The raindrop sensor may further include a controller that receives the output signal from the readout circuit, determines the magnitude of vibration of the sensing member based on the magnitude of the output signal, and determines that raindrops have contacted if the magnitude of the vibration is greater than or equal to a threshold value have.

The controller may determine that raindrops have contacted when the magnitude of the vibration of the sensing member measured within a preset time period meets a preset pattern condition. In this case, the pattern condition may be a condition in which an event in which the magnitude of vibration is greater than or equal to a threshold value within a time period occurs more than a preset number of times.

The readout circuit includes: a signal processing circuit that performs signal processing on the first electrical signal and the second electrical signal to generate a third electrical signal having a differential frequency component; and generating as an output signal at least one of a digital value having a magnitude corresponding to the magnitude of the differential frequency component, an analog signal having a magnitude corresponding to the magnitude of the differential frequency component, and an AC signal having an amplitude corresponding to the magnitude of the differential frequency component. It may include a signal conversion circuit.

A readout circuit for a vibration detection rain drop sensor according to an embodiment of the present invention is a first electricity formed in a first resonance circuit spaced apart from a sensing member in a first direction and connected to a sensing coil disposed to face the sensing member receiving a signal, receiving a second electrical signal formed in the second resonant circuit and having a second resonant frequency, and performing signal processing on the first electrical signal and the second electrical signal to obtain the first resonant frequency and the second resonant frequency a signal processing circuit for generating a third electrical signal having a differential frequency component corresponding to a difference between frequencies; and a signal conversion circuit generating an output signal having a magnitude corresponding to the differential frequency component and having a magnitude corresponding to a displacement of the sensing member in the first direction with respect to the sensing coil.

A method of operating a vibration detection rain drop sensor according to an embodiment of the present invention includes a first resonance frequency from a first resonance circuit connected to a sensing coil spaced apart from a sensing member in a first direction and disposed to face the sensing member 1 receiving an electrical signal; receiving a second electrical signal having a second resonant frequency from a second resonant circuit; generating a third electrical signal having a differential frequency component corresponding to a difference between the first resonant frequency and the second resonant frequency by performing signal processing on the first electrical signal and the second electrical signal; and generating an output signal having a magnitude corresponding to the differential frequency component and having a magnitude corresponding to a displacement of the sensing member in the first direction with respect to the sensing coil.

According to the raindrop sensor of the present invention, it is possible to accurately distinguish contact of raindrops from changes in humidity caused by dew, fog or frost without additional sensing means.

According to the raindrop sensor of the present invention, displacement in the first direction of the sensing member due to a force applied in the first direction perpendicular to the substrate can be detected by inductive coupling with the sensing coil, and through this, the amount of moisture or humidity Regardless of the change, it is possible to detect the presence or absence of contact with raindrops.

According to the raindrop sensor of the present invention, a configuration for changing the frequency of an input electrical signal is not required, so power consumption can be reduced. In addition, by detecting a minute shift in the resonant frequency, vibration caused by contact of raindrops can be detected, and the sensitivity to vibration can be increased.

The raindrop sensor of the present invention may be used alone, or when used together with other known sensing means, the effect due to the combination may be increased. The raindrop sensor of the present invention can provide unique information that does not overlap with information provided by other sensing means, and when combined with other sensing means, is also efficient in that it can provide comprehensive information on weather conditions. .

Since the raindrop sensor of the present invention can directly detect the magnitude of the vibration of an object on which the sensor is installed, there is no restriction on the location where the sensor is installed. In detecting , it is possible to comprehensively determine using the magnitude and frequency of vibration, providing much more accurate information.

1 is a diagram illustrating at least a part of a vibration detection raindrop sensor according to an embodiment of the present invention.
2 is a block diagram illustrating another part of a vibration detection raindrop sensor according to an embodiment of the present invention.
3 is a diagram illustrating an operating principle of a vibration detection rain drop sensor according to an embodiment of the present invention.
4 is a block diagram illustrating an operation of a vibration detection rain drop sensor according to an embodiment of the present invention.
5 is an operation flowchart illustrating a method of operating a vibration detection rain drop sensor according to an embodiment of the present invention.
6 is an operation flowchart illustrating a method of operating a vibration detection rain drop sensor according to an embodiment of the present invention.

In addition to the above objects, other objects and features of the present invention will become apparent through the description of the embodiments with reference to the accompanying drawings. A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

Raindrop sensors are generally placed on the window of a vehicle and used to detect whether raindrops are in contact with the window of the vehicle. Judgment is often The raindrop sensor of the present invention was derived from the purpose of solving the problems of the prior art.

On the other hand, raindrop sensors can be installed not only in vehicles but also in livestock houses used in livestock farms. In order to control the behavior of livestock, it is very important to distinguish whether it is actually raining, dew or frost.

The raindrop sensor of the present invention is not only used as a sensing means for operating a vehicle wiper, but is also installed on the roof of a livestock farmhouse to obtain accurate weather information to control the behavior of livestock. can be

In addition, the raindrop sensor of the present invention may be used when it is necessary to obtain accurate weather information for work such as a construction site.

Known technologies disclosed by Korean Patent Laid-Open Patent KR 10-2021-0015194 "Rain sensor for vehicle, wiper system and wiper control method using same", Korean Patent KR 10-2327610 "Rain sensor and wiper driving device including the same", etc. , may be included as a part of the configuration of the present invention within the scope consistent with the purpose of the present invention. At this time, since the fact that is clearly understood by those skilled in the art by the prior documents may obscure the gist of the present invention, the detailed description will be omitted, and the prior documents will be introduced instead.

Hereinafter, the vibration detection raindrop sensor, the readout circuit included in the vibration detection raindrop sensor, and the operation method of the vibration detection raindrop sensor according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6 .

1 is a diagram illustrating at least a part of a vibration detection raindrop sensor according to an embodiment of the present invention.

Referring to FIG. 1 , the vibration sensing raindrop sensor 100 includes a sensing coil 110 , a substrate 120 , a sensing member 130 , and a support member 140 .

The sensing member 130 may be implemented by including a metal plate or a conductive material through which current can flow through the FPCB.

In another embodiment of the present invention, a coil (not shown) may be formed on the sensing member 130 .

The support member 140 serves to support the sensing member 130 . The support member 140 may include a means for absorbing vibration. For example, a means for absorbing vibration such as a spring may be included.

A sensing coil 110 pattern is formed on one surface of the substrate 120 , and the sensing coil 110 is electrically connected to a first resonance circuit (not shown in FIG. 1 ).

The first resonant circuit may be formed on the substrate 120 or may be formed as a separate individual passive element.

The sensing member 130 is disposed to be spaced apart from the substrate 120 in a first direction (z-axis direction) perpendicular to the substrate 120 . The sensing coil 110 is disposed on one surface of the substrate 120 , the sensing coil 110 and the sensing member 130 are disposed to face each other, and are spaced apart from the sensing coil 110 by a predetermined distance in the first direction. A sensing member 130 is disposed.

The sensing coil 110 and the sensing member 130 are inductively coupled to each other.

When the sensing member 130 receives a force in the first direction and moves in the first direction, the inductance formed in the sensing coil 110 may change by the displacement of the sensing member 130 in the first direction with respect to the sensing coil 110 . can

When the inductance of the sensing coil 110 is detected and the change in inductance is tracked, the displacement of the sensing member 130 with respect to the sensing coil 110 in the first direction can be detected, and the sensing member 130 moves in the first direction. Vibration can be tracked.

2 is a block diagram illustrating another part of a vibration detection raindrop sensor according to an embodiment of the present invention.

The rain drop sensor 100 may include a readout circuit (ROIC, Readout IC) 150 , and a controller 170 . In this case, the controller 170 may be configured as an MCU, and may control the overall operation of the vibration detection rain drop sensor 100 .

The readout circuit 150 may be connected to the sensing coil 110 . In this case, the readout circuit 150 may be directly connected to the sensing coil 110 , or may be connected to the sensing coil 110 via a first resonance circuit (not shown in FIG. 2 ).

A part or all of the readout circuit 150 and the controller 170 may be formed on the substrate 120 or on a separate substrate (not shown).

The readout circuit 150 detects a change in inductance formed in the sensing coil 110 inductively coupled to the sensing member 130 by displacement of the sensing member 130 in the first direction with respect to the sensing coil 110 . Sensing may generate an output signal Sout, and transmit the output signal Sout to the controller 170 .

3 is a diagram illustrating an operating principle of a vibration detection rain drop sensor according to an embodiment of the present invention.

The rain drop sensor 100 may include a first resonance circuit 152 , a first oscillator 156 , a second resonance circuit 154 , and a second oscillator 158 .

At this time, the first resonant circuit 152 , the first oscillator 156 , the second resonant circuit 154 , and the second oscillator 158 are deeply involved in the operation of the readout circuit 150 in the raindrop sensor 100 , but , and the area of the readout circuit 150 are not necessarily included in the readout circuit 150 . The first resonance circuit 152 , the first oscillator 156 , the second resonance circuit 154 , and the second oscillator 158 may be located inside the readout circuit 150 , and the readout circuit 150 . ) can also be arranged as independent individual elements outside the . In this case, some of the first resonance circuit 152 , the first oscillator 156 , the second resonance circuit 154 , and the second oscillator 158 are located inside the readout circuit 150 , and the remaining parts are readout It may be disposed outside the circuit 150 .

The first resonance circuit 152 is electrically connected to the sensing coil 110 .

The first oscillator 156 may apply the first AC signal to the first resonance circuit 152 . The first oscillator 156 may be disposed in parallel with the first resonance circuit 152 .

The inductance formed in the sensing coil 110 may be formed by inductive coupling between the sensing member 130 and the sensing coil 110 . A change in inductance formed in the sensing coil 110 may be affected by a displacement of the sensing member 130 with respect to the sensing coil 110 in the first direction.

Based on the combined RLC impedance in which the inductance formed in the sensing coil 110 is coupled to the first resonant circuit 152 , the first resonant frequency ω1 of the first electrical signal formed in the first resonant circuit 152 is can be decided.

The second resonance circuit 154 is electrically connected to the reference coil 112 .

The second oscillator 158 may apply the second AC signal to the second resonance circuit 154 . The second oscillator 158 may be disposed in parallel with the second resonance circuit 154 .

The second oscillator 158 may have the same electrical characteristics as the first oscillator 156 or may have equivalent electrical characteristics. The second resonant circuit 154 may have the same electrical characteristics as the first resonant circuit 152 or may have equivalent electrical characteristics. The electrical characteristics may include impedance characteristics.

The reference coil 112 should be disposed at a position where it is not inductively coupled to the sensing member 130 , and may be disposed on the other side of the substrate 120 according to an embodiment. The reference coil 112 is a means for equalizing or equivalently matching the initialized impedance characteristics of the first resonant circuit 152 and the impedance characteristics of the second resonant circuit 154 , so the same or equivalent to the sensing coil 110 . can have characteristics.

The second resonance circuit 154 may be used as a reference circuit. Since the second resonant circuit 154 may have the same or equivalent electrical characteristics as the state in which the first resonant circuit 152 is initialized, the displacement of the sensing member 130 in the first direction with respect to the sensing coil 110 is If it is negligibly small, ideally the first resonant frequency ω1 of the first resonant circuit 152 and the second resonant frequency ω2 of the second electrical signal formed in the second resonant circuit 154 are the same. can

As the displacement of the sensing member 130 with respect to the sensing coil 110 in the first direction increases, the inductance formed in the sensing coil 110 deviates from the initialized value, and the first resonant frequency ( A shift value at which ω1) deviates from the initialized value of the first resonant frequency ω1 may be large.

The displacement of the sensing member 130 with respect to the sensing coil 110 in the first direction may be obtained by calculating the difference between the first resonant frequency ω1 and the second resonant frequency ω2 .

For convenience of explanation, a separate inductor other than the coils 110 and 112 is illustrated in the resonant circuits 152 and 154, but this may be understood to mean a separate inductor, or it may be understood as showing a parasitic inductance. It should not be understood that the spirit of the present invention is reduced or limited by the embodiment shown in FIG. 3 .

The conventional technique counts each of the first resonant frequency (ω1) and the second resonant frequency (ω2) and then subtracts them, but this prior art method requires a long time to obtain the resonant frequency and requires a large amount of energy .

Another prior art is a method of detecting the amplitude of a resonant signal and then converting it to a resonant frequency in order to obtain a resonant frequency. This prior art also has low sensitivity and a large amount of energy required for calculation. In this method, the frequency with the largest amplitude is recognized as the resonant frequency by measuring the amplitude while changing (scanning) multiple frequencies within a specific band, so the frequency resolution depends on the scan resolution, and in order to increase the frequency resolution, It takes a very long time, and there is a problem that precise measurement is difficult.

The readout circuit 150 of the present invention performs signal processing on the first electric signal and the second electric signal instead of obtaining each of the first resonant frequency ω1 and the second resonant frequency ω2 to obtain the first resonant frequency A third electrical signal having a differential frequency component corresponding to a difference between (ω1) and the second resonant frequency (ω2) may be generated. This configuration of the present invention has the advantage of being able to measure a precise frequency shift by a single measurement without needing to count the frequencies and without changing the frequencies of a plurality of frequencies. Therefore, only a short time is required to measure the resonance frequency shift and the displacement in the first direction, and the measurement can be sufficiently performed even with a small amount of energy. The vibration detection raindrop sensor 100 may include a separate interface (not shown) for charging the power supply 180 , but according to the present invention, it is possible to reduce the charging frequency of the power supply 180 . there is When the vibration detection rain drop sensor 100 is a battery type, there is an effect of reducing the battery replacement frequency or extending the lifespan of the device 100 .

In addition, since the shift of the resonant frequency is measured rather than the resonant frequency itself, the dynamic range is large, so that the displacement of the sensing member 130 in the first direction with respect to the sensing coil 110 has a very large value, unlike the normal case It is possible to judge the overall situation with simple measurements without errors. The conventional vibration detection sensor is designed to operate normally within the range of the normal displacement vibration or the magnitude of the displacement. Therefore, in the case of a conventional raindrop sensor, when the magnitude of vibration or displacement has a very large value outside the assumed range of the magnitude of vibration or displacement, for example, a foreign object is impacted or an object on which a vibration detection sensor is installed (eg, a window of a vehicle) , the roof of livestock farmhouses), when vibration occurs due to structural problems, it is difficult to accurately classify it and respond appropriately.

However, since the raindrop sensor 100 of the present invention can correspond to a very wide dynamic range, even when the magnitude of vibration or displacement has a very large value outside the initially assumed range, it can robustly measure the magnitude of vibration or displacement. And based on the measured value, it is possible to derive a comprehensive judgment about the situation in which the vibration detection sensor and the object in which the sensor is installed are related.

In this case, the vibration detection raindrop sensor 100 determines that the raindrop sensor 100 itself or the object in which the sensor 100 is installed is not a suitable situation for use, and sets a rating for the risk that may occur during use. A warning signal can be derived based on Since the degree of danger will be greater than the normal situation, the strength of the warning signal may be set accordingly.

Alternatively, if the measured value is out of a range that can occur in an actual situation, the measurement result may be treated as an error and the magnitude of the vibration may be measured again.

On the other hand, the conventional capacitive-based raindrop sensor typically requires a time of several hundred milliseconds to several seconds to detect a change in capacitance and determine the situation, but the raindrop sensor 100 of the present invention is a water drop sensor 100 of the present invention. In addition to being unaffected, there is a difference in which the results can be completely detected within a few hundred microseconds to several milliseconds in the process of judging the magnitude of displacement and vibration.

A typical range of frequencies used in the raindrop sensor 100 of the present invention may be several MHz or hundreds of kHz, but the spirit of the present invention is not limited to this embodiment. The frequency band that the raindrop sensor 100 of the present invention can actually measure is very wide, and it can respond to a large change in the magnitude of vibration or displacement based on a high dynamic range.

4 is a block diagram illustrating an operation of a vibration detection rain drop sensor according to an embodiment of the present invention.

5 is an operation flowchart illustrating a method of operating a vibration detection rain drop sensor according to an embodiment of the present invention.

6 is an operation flowchart illustrating a method of operating a vibration detection rain drop sensor according to an embodiment of the present invention.

1 to 6 , the readout circuit 150 in the raindrop sensor 100 may include at least a signal processing circuit 160 and a signal conversion circuit 162 .

The signal processing circuit 160 included in the readout circuit 150 in the rain drop sensor 100 receives the first electrical signal from the first resonance circuit 152 ( S510 ), and receives the second electrical signal from the second resonance circuit 154 . 2 It is possible to receive an electrical signal (S520).

The signal processing circuit 160 included in the readout circuit 150 in the rain drop sensor 100 performs signal processing on the first electrical signal and the second electrical signal (S530) to obtain the first resonant frequency ω1 and the second electrical signal. A third electrical signal having a differential frequency component corresponding to a difference between the two resonant frequencies ω2 may be generated. In the process of generating the third electrical signal, a multiplication operation between signals may be used, and in this case, a formula of a sine or cosine function, which is a well-known principle, may be used. In another embodiment of the present invention, synthetic signal processing for the first electrical signal and the second electrical signal may be used, and in this case, a third electrical signal having a differential frequency component may be generated. Signal processing for the first electrical signal and the second electrical signal may be performed in at least one of an analog domain, a digital domain, and an analog-digital mixed domain.

The signal conversion circuit 162 included in the readout circuit 150 in the rain drop sensor 100 receives the third electrical signal, and generates an output signal Sout having a magnitude corresponding to the differential frequency component of the third electrical signal. can be generated (S540). In this case, the magnitude of the output signal Sout is also a magnitude corresponding to the displacement of the sensing member 130 in the first direction with respect to the sensing coil 110 .

The signal conversion circuit 162 may generate the output signal Sout so that the controller 170 may obtain information about the displacement of the sensing member 130 in the first direction with respect to the sensing coil 110 . In this case, the output signal Sout may be converted to have a magnitude proportional to the differential frequency component.

The signal conversion circuit 162 may generate an AC signal or a pulse signal having a magnitude proportional to the differential frequency component as the output signal Sout. In this case, the magnitude of the output signal Sout may be any one of an amplitude of a voltage/current, a frequency of an AC signal, a frequency of a pulse signal, and/or a duty cycle.

The signal conversion circuit 162 may generate an analog DC signal or a pulse signal having a magnitude proportional to the differential frequency component as the output signal Sout. In this case, the level of the output signal Sout may be any one of a level of voltage/current, a level of power, and/or a level of energy transferred per unit time.

The signal conversion circuit 162 may generate a digital signal having a magnitude proportional to the differential frequency component as the output signal Sout. In this case, the size of the output signal Sout may correspond to a value indicated by a series of digital signals.

The signal conversion circuit 162 may scale up or down to an appropriate scale in the process of converting the differential frequency component into the output signal Sout.

As described above, when the magnitude of the vibration or displacement greatly deviates from the initially assumed range, the magnitude of the output signal Sout may also deviate from the designed range. In this case, the rain drop sensor 100 may generate information on such a sudden situation and process the unexpected situation inside the vibration detection rain drop sensor 100 or warn the user.

Ideally, the initialized first resonant frequency ω1 and the second resonant frequency ω2 are the same, but there may be a slight offset in practice. The rain drop sensor 100 may detect an offset through a calibration process, and may add R/L/C to the first resonance circuit 152 and/or the second resonance circuit 154 to compensate for the offset.

Alternatively, the rain drop sensor 100 may generate an output signal Sout having a magnitude compensated for the offset when generating the output signal Sout after detecting the offset (S540). Alternatively, when the controller 170 of the raindrop sensor 100 determines the magnitude of the vibration based on the output signal Sout ( S610 ), the controller 170 may compensate the determination value of the magnitude of the vibration using the offset information.

In the actual field, due to the influence of temperature, it may be affected by the detection of the magnitude of vibration, the operation of the circuit, and the magnitude of the signal. Accordingly, in at least one of generating the output signal Sout ( S540 ), determining the magnitude of the vibration ( S610 ), and/or comparing the magnitude of the vibration with a threshold ( S620 ), a temperature-related variable is considered and compensated for. can be obtained.

The raindrop sensor 100 of the present invention does not need to directly measure the amplitudes or resonance frequencies of the first electric signal and the second electric signal, but according to an embodiment of the present invention, the voltage/current of the first electric signal After measuring the amplitude and the amplitude of the voltage/current of the second electrical signal together, a secondary measurement value of the magnitude of the vibration may be obtained based on the amplitude measurement result. In this case, the rain drop sensor 100 may cross-verify the primary measurement value of the magnitude of the vibration based on the resonance frequency shift using the secondary measurement value.

The controller 170 receives the output signal Sout from the readout circuit 150, and determines the displacement of the sensing member 130 with respect to the sensing coil 110 in the first direction based on the magnitude of the output signal Sout. It can be determined (S610).

The controller 170 may compare the magnitude of the vibration with the threshold value (T) (S620), and if the magnitude of the vibration is greater than or equal to the threshold value (T), it may be determined/determined that the raindrop has actually impacted or contacted (S630). When the impact/contact of raindrops is determined, the determination result may be transmitted to the user. The determination result may be transmitted to the user using visual means (display, flashing of warning lights), audible means (speaker, alarm), tactile means (vibration), and the like.

When the raindrop sensor is used for a window of a vehicle, when the impact/contact of raindrops is determined, it is possible to notify the user of the start of the operation of the wiper and operate the wiper. In this case, the degree of rain may be determined by the controller 170 in consideration of the magnitude and frequency of vibration. By quantifying the degree of rain, the controller 170 may transmit necessary information to a controller (not shown) of the vehicle to adjust the operation frequency of the wiper.

Since the capacitive raindrop sensor of the prior art can detect only raindrops falling on the location where the sensor is installed, there is a big limitation in selecting the location where the sensor is installed. However, since the raindrop sensor of the present invention can measure the magnitude and frequency of vibration, there is almost no restriction on the location where the sensor is installed.

The capacitive raindrop sensor of the prior art can detect only raindrops falling on the location where the sensor is installed, making it difficult to detect when it rains lightly, but the raindrop sensor of the present invention can detect contact of raindrops even when it rains heavily can

The capacitive raindrop sensor of the prior art can detect the size of only raindrops falling on the location where the sensor is installed, so it is inaccurate to detect the overall amount of rain, but the raindrop sensor of the present invention detects the size and frequency of the overall vibration Therefore, the amount of the overall ratio can be accurately detected.

In this case, the following pattern conditions may be set in order to distinguish a case where foreign substances such as secretions from birds other than raindrops impact from a case where raindrops impact. For example, a pattern condition such as determining that a raindrop has impacted can be set only when a case in which a pattern in which other vibrations are continuous is repeated 2-3 times within 1-2 seconds after the first vibration is sensed is satisfied.

In addition, only one sensor may be used in the window of a car, and when it is installed on the roof of a livestock farmhouse, the area that one sensor has to cover is too wide, so multiple sensors are disposed, and if only one sensor detects vibration, It is determined as a foreign material, and when vibration is irregularly detected by a plurality of sensors, it may be determined as raindrops.

In addition, since the raindrop sensor of the present invention can measure the magnitude and frequency of vibration, if regular vibration rather than irregular vibration is detected, it may be determined as vibration caused by artificial manipulation rather than raindrops regardless of the magnitude of vibration. There will be. Unlike the capacitive raindrop sensor of the prior art, the raindrop sensor of the present invention can be applied to a variety of uses. have.

The raindrop sensor 100 of the present invention may set at least one threshold value in measuring the shift value of the resonance frequency.

The first threshold value may be set as a criterion for determining whether the shift value of the resonance frequency causes a significant change. For example, when the shift value of the resonance frequency is changed due to measurement noise, etc., since it may be difficult to recognize this as a measurement of the magnitude of the normal vibration, the first threshold value may be set.

The second threshold value may be set in consideration of an offset with respect to a difference in resonant frequencies. When the offset is detected, a second threshold value based on the offset is considered in the signal processing ( S530 ), the conversion process ( S540 ), and the determination process ( S610 ) to obtain a valid determination result for the magnitude of the vibration.

Another plurality of threshold values may be set to determine a sudden situation in which the magnitude of vibration is outside the initially assumed range (which may be caused by an impact of a foreign material or a structural problem of an object in which a sensor is installed).

Another plurality of threshold values may be set based on a hardware range that the output signal Sout may have. In the case of having an output value in a range that cannot be accommodated by scaling up/down in the signal conversion process ( S540 ), accurate information may be auxiliaryly transmitted to the controller 170 through a separate signal.

Another plurality of threshold values may be set in response to a measurement result in a range that is not physically possible. In this case, the measurement result may be regarded as an error.

The first embodiment of the rain drop sensor of the present invention is not affected by a change in capacitance, that is, it can detect a change in inductance independently of a change in capacitance. At this time, the sensing coil and the sensing member are spaced apart along a first direction (z-axis direction) perpendicular to the substrate, and the change in inductance is the change in the distance between the sensing coil and the sensing member in the first direction (the first direction of the sensing member with respect to the sensing coil). displacement in one direction).

A second embodiment of the rain drop sensor of the present invention includes a vibration sensing rain drop sensor that detects a displacement of a sensing member in a first direction based on a change in inductance, and a capacitive type that detects a change in humidity based on a change in capacitance. It may also include a raindrop sensor.

In the second embodiment, it can be determined that rain is falling only when significant signal changes (vibration and humidity changes) are detected in both the vibration detection raindrop sensor and the capacitive raindrop sensor. In this case, the vibration detection raindrop sensor provides information that does not overlap with the capacitive raindrop sensor. Therefore, the synergy can be greater when the vibration-sensing raindrop sensor and the capacitive raindrop sensor are combined.

The circuit operation method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

However, the present invention is not limited or limited by the examples. Like reference numerals in each figure indicate like elements. Length, height, size, width, etc. introduced in the embodiments and drawings of the present invention may be exaggerated to help understanding.

As described above, in the present invention, specific matters such as specific components, etc., and limited embodiments and drawings have been described, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , various modifications and variations are possible from these descriptions by those of ordinary skill in the art to which the present invention pertains.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

100: vibration detection raindrop sensor
110: sensing coil 112: reference coil
120: substrate 130: sensing member 140: support member
150: ROIC/readout circuit
152: first resonant circuit 154: second resonant circuit
160: signal processing circuit 162: signal conversion circuit
170: controller/MCU

Claims (8)

lack of sensing;
a sensing coil spaced apart from the sensing member in a first direction and disposed to face the sensing member;
a first resonance circuit connected to the sensing coil and configured to receive a first AC signal from a first oscillator;
a second resonant circuit for receiving a second AC signal from the second oscillator; and
Receives a first electrical signal formed in the first resonant circuit and having a first resonant frequency, and receives a second electrical signal formed in the second resonant circuit and having a second resonant frequency, the first electrical signal and By performing signal processing on the second electrical signal, a third electrical signal having a differential frequency component corresponding to a difference between the first resonant frequency and the second resonant frequency is generated, and a magnitude corresponding to the differential frequency component is determined. a read-out circuit for generating an output signal having a size formed to correspond to a displacement of the sensing member in the first direction with respect to the sensing coil;
Vibration detection rain drop sensor comprising a. According to claim 1,
a controller that receives the output signal from the readout circuit, determines the magnitude of the vibration of the sensing member based on the magnitude of the output signal, and determines that raindrops have contacted if the magnitude of the vibration is greater than or equal to a threshold value;
Vibration detection rain drop sensor further comprising. 3. The method of claim 2,
The controller determines that the raindrop has contacted when the magnitude of the vibration of the sensing member measured within a preset time period meets a preset pattern condition,
The pattern condition is a vibration detection rain drop sensor that is a condition in which an event in which the magnitude of the vibration is greater than or equal to the threshold value within a time interval occurs more than a preset number of times. According to claim 1,
The readout circuit is
a signal processing circuit for generating the third electrical signal having the differential frequency component by performing signal processing on the first electrical signal and the second electrical signal; and
at least one of a digital value having a magnitude corresponding to the magnitude of the differential frequency component, an analog signal having a magnitude corresponding to the magnitude of the differential frequency component, and an AC signal having an amplitude corresponding to the magnitude of the differential frequency component as the output signal a signal conversion circuit generating as
Vibration detection rain drop sensor comprising a. A first electrical signal spaced apart from the sensing member in a first direction and connected to a sensing coil disposed to face the sensing member and formed in a first resonance circuit for receiving a first AC signal from a first oscillator and having a first resonance frequency is formed in a second resonant circuit for receiving a second AC signal from a second oscillator and receives a second electrical signal having a second resonant frequency, and a signal for the first electrical signal and the second electrical signal a signal processing circuit that performs processing to generate a third electrical signal having a differential frequency component corresponding to a difference between the first resonant frequency and the second resonant frequency; and
a signal conversion circuit for generating an output signal having a magnitude corresponding to the differential frequency component and configured to correspond to a displacement of the sensing member in the first direction with respect to the sensing coil;
A readout circuit for a vibration detection raindrop sensor comprising a. A first electrical signal having a first resonant frequency is received from a first resonance circuit that is spaced apart from the sensing member in a first direction and is connected to a sensing coil disposed to face the sensing member and receives a first AC signal from the first oscillator to do;
receiving a second electrical signal having a second resonant frequency from a second resonant circuit that receives a second AC signal from a second oscillator;
generating a third electrical signal having a differential frequency component corresponding to a difference between the first resonant frequency and the second resonant frequency by performing signal processing on the first electrical signal and the second electrical signal; and
generating an output signal having a magnitude corresponding to the differential frequency component and having a magnitude formed to correspond to displacement of the sensing member in the first direction with respect to the sensing coil;
A method of operating a vibration detection rain drop sensor comprising a. 7. The method of claim 6,
determining the magnitude of the vibration of the sensing member based on the magnitude of the output signal; and
determining that raindrops have contacted if the magnitude of the vibration is greater than or equal to a threshold;
Method of operation of the vibration detection rain drop sensor further comprising. 8. The method of claim 7,
The step of determining that the raindrop has contacted
If the magnitude of the vibration of the sensing member measured within a preset time period meets a preset pattern condition, it is determined that the raindrop has contacted,
The pattern condition is a condition in which an event in which the magnitude of the vibration is greater than or equal to the threshold value within a time interval occurs more than a preset number of times.

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