KR102503129B1 - Rain sensor and wiper driving device including same - Google Patents

Abstract

A rain sensor according to an embodiment includes a substrate; a first sensing electrode disposed on the substrate; and a second sensing electrode disposed on the substrate and spaced apart from the first sensing electrode by a predetermined distance, wherein the distance between the first sensing electrode and the second sensing electrode changes toward one direction of the substrate.

Description

Rain sensor and wiper driving device including the same {RAIN SENSOR AND WIPER DRIVING DEVICE INCLUDING SAME}

The present invention relates to a rain sensor, and more particularly, to a rain sensor capable of accurately detecting a change in capacitance caused by a very small amount of raindrops or a large amount of raindrops, and a wiper driving device including the same.

In general, a wiper is installed on a front windshield of a vehicle to overcome visibility disturbance caused by rainwater in rainy weather, and the intermittent speed of the wiper is controlled in stages according to the degree of rainwater falling. However, since the wiper speed control system is adjusted in only a few steps, it is difficult to move the wiper at a speed desired by the driver according to the amount of rainwater.

In order to overcome this problem, the circuit board equipped with the light source and the sensor, which is a light receiving element, is placed obliquely with respect to the windshield surface, thereby minimizing the effect of the light reflected from the windshield surface, while receiving only the optical signal reflected from the raindrops themselves. There is a configuration that can increase the lane sensing efficiency by doing so. That is, the light directly reflected from the windshield escapes outside the light-receiving range of the light-receiving element and is reflected on the windshield to minimize the amount of light received by the light-receiving element, while only the amount of light reflected from the raindrops is received by the light-receiving element. A circuit board equipped with a light source and a light-receiving element is arranged at an angle with respect to the surface of the windshield so as to detect only diffuse reflection signals.

However, even in the case of a product in which the light source and the light receiving element are arranged obliquely with respect to the windshield surface of the vehicle by the circuit board as described above, there are cases where the light emitted from the light source is directly absorbed by the light receiving element, so in terms of rain sensing efficiency, It is somewhat incomplete and lacking. That is, the light emitted from the light source spreads in a certain angular range. Even if the light source and the light receiving element are disposed obliquely with respect to the surface of the windshield, some of the light in addition to the light falling out of the windshield is directly directed toward the light receiving element. Due to the interference light absorbed by the light-receiving element, there is a problem of slightly degrading the raindrop sensing efficiency, and because of this, there is a somewhat insufficient aspect to ensure perfection in terms of rain sensing efficiency.

Even when the design is designed to minimize ambient interference light caused by the headlights of passing vehicles as described above, interference light that cannot be blocked inevitably occurs, and the light-sensing rain sensor itself is a very sensitive sensor product, so it is not blocked yet. Since it is inevitably affected by a small amount of ambient light, it is inevitable to have a limit to produce a highly precise rain sensing effect. In addition, in order to implement a structure for minimizing the influence of ambient light as described above, it is inevitable to have a rather complicated structure. It is an inevitable situation that it is somewhat inefficient in terms of productivity and has limitations such as slightly increasing product cost.

In an embodiment according to the present invention, a rain sensor capable of determining whether or not it rains and the amount of rain by detecting a change in impedance of a carbon micro coil caused by raindrops falling on a windshield of a vehicle and a wiper driving device including the same are provided.

In addition, the embodiment provides a rain sensor capable of determining whether or not it rains and the amount of rain by using a device including a carbon micro coil, and controlling whether or not the wiper is driven and the driving speed of the wiper accordingly, and a wiper driving device including the same. .

In addition, in the embodiment according to the present invention, a rain sensor capable of accurately detecting not only a very small amount of raindrops but also a large amount of raindrops through pattern design of sensing electrodes and a wiper driving device including the same are provided.

The technical tasks to be achieved in the proposed embodiment are not limited to the technical tasks mentioned above, and other technical tasks not mentioned are clear to those skilled in the art from the description below to which the proposed embodiment belongs. will be understandable.

A rain sensor according to an embodiment includes a substrate; a first sensing electrode disposed on the substrate; and a second sensing electrode disposed on the substrate and spaced apart from the first sensing electrode by a predetermined distance, wherein the distance between the first sensing electrode and the second sensing electrode changes toward one direction of the substrate.

In addition, at least one of the first sensing electrode and the second sensing electrode is disposed on the substrate while extending in the one direction, and a width gradually increases or decreases in the one direction.

In addition, the first sensing electrode and the second sensing electrode have mutually symmetrical shapes.

In addition, a surface of the first sensing electrode facing the surface of the second sensing electrode has a curved surface.

In addition, a surface of the second sensing electrode facing the curved surface of the first sensing electrode has a curved surface.

In addition, the first sensing electrode includes a first body extending in one direction, a first branch electrode and a second branch electrode protruding from the first body toward the second sensing electrode and spaced apart from each other by a predetermined distance. The second sensing electrode includes a second body extending in one direction, a third branch electrode protruding from the second body toward the first sensing electrode and spaced apart from each other by a predetermined distance, and a fourth branch electrode. and a branch electrode, wherein the third branch electrode is disposed between the first branch electrode and the second branch electrode, and the fourth branch electrode is disposed below the second branch electrode, and the first branch electrode and the second branch electrode are disposed. The first distance between the three branch electrodes, the second distance between the third branch electrode and the second branch electrode, and the third distance between the second branch electrode and the fourth branch electrode are all different.

In addition, the interval between each of the branch electrodes satisfies the following condition.

1st interval < 2nd interval < 3rd interval

The reaction layer is disposed on the substrate and buries the first sensing electrode and the second sensing electrode, wherein the reaction layer changes at least one of force and dielectric constant caused by rain or not. Impedance characteristics change according to , and the first and second sensing electrodes output detection signals according to changes in the impedance characteristics of the reaction layer.

In addition, a driving unit disposed under the substrate, connected to the first and second sensing electrodes, and processing the output sensing signal; and a protective layer disposed surrounding the substrate, the driving unit, and the reaction layer.

In addition, the reaction layer includes a carbon micro coil material.

On the other hand, the wiper driving device according to the embodiment includes a windshield; a sensor unit attached to the first surface of the windshield and changing an impedance value by an object contacting the second surface of the windshield; And a control unit that receives a detection signal according to the amount of change in the impedance value through the sensor unit, determines whether or not it rains based on the received detection signal, and drives a wiper according to the determined whether or not it rains, wherein the sensor unit, A substrate, a first sensing electrode disposed on the substrate, a second sensing electrode disposed on the substrate and separated from the first sensing electrode by a predetermined distance, and disposed on the substrate, the first and second sensing electrodes A buried reaction layer, a driver disposed under the substrate and connected to the first and second sensing electrodes, and a protective layer surrounding the substrate, the reaction layer, and the drive unit, wherein the first sensing electrode and A gap between the second sensing electrodes changes toward one direction of the substrate.

In addition, at least one of the first sensing electrode and the second sensing electrode is disposed on the substrate while extending in the one direction, and a width gradually increases or decreases in the one direction.

In addition, the first sensing electrode and the second sensing electrode have mutually symmetrical shapes.

In addition, a surface of the first sensing electrode facing the surface of the second sensing electrode has a curved surface.

In addition, the second sensing electrode has a curved surface facing the curved surface of the first sensing electrode.

In addition, the first sensing electrode includes a first body extending in one direction, a first branch electrode and a second branch electrode protruding from the first body toward the second sensing electrode and spaced apart from each other by a predetermined distance. The second sensing electrode includes a second body extending in one direction, a third branch electrode protruding from the second body toward the first sensing electrode and spaced apart from each other by a predetermined distance, and a fourth branch electrode. and a branch electrode, wherein the third branch electrode is disposed between the first branch electrode and the second branch electrode, and the fourth branch electrode is disposed below the second branch electrode, and the first branch electrode and the second branch electrode are disposed. The first distance between the three branch electrodes, the second distance between the third branch electrode and the second branch electrode, and the third distance between the second branch electrode and the fourth branch electrode are all different.

In addition, the reaction layer includes a carbon micro coil material.

In addition, the control unit uses a rainfall detection unit that outputs an output value corresponding to a difference value between a first frequency and a predetermined second frequency according to a change in the impedance value of the sensor unit, and an output value output through the rainfall detection unit. and a determination unit for determining whether or not there is rainfall and the amount of rainfall, and determining a wiper operating condition according to the determination result, wherein the first frequency changes in response to a change in the inductance value of the carbon microcoil according to whether or not there is rain and the amount of rainfall do.

In addition, the rainfall sensor unit may include a first frequency generator outputting the first frequency having an oscillation frequency corresponding to a change in the impedance of the sensor unit, and a second frequency generator outputting the second frequency corresponding to a preset reference oscillation frequency. A generator, a difference frequency generator outputting a difference value between the first frequency and the second frequency, and a filter filtering the difference value output through the difference frequency generator within a predetermined filtering area.

In addition, the filtering region of the filter is set based on a first threshold value for a change in inductance value of the carbon microcoil according to the occurrence of the rain, and the determination unit determines the first threshold value and other values except for the rainfall. Based on the second threshold value for the change in the inductance value of the material, materials generating the difference value are respectively distinguished.

According to the embodiment, when rain occurs, the driver's convenience can be improved by reacting immediately to the occurrence of rain and driving the wiper under driving conditions according to the amount of rain.

In addition, according to the embodiment, it is possible to provide a rain sensor with differentiated characteristics (response characteristics, precision, accuracy, power consumption, miniaturization, etc.) compared to the existing optical method by determining whether or not there is rainfall and amount of rainfall using a carbon micro coil can

In addition, according to the embodiment, since the external environment does not affect the rain sensor, an additional correction sensor for correcting the characteristics of the rain sensor is unnecessary, and thus costs can be reduced.

In addition, according to the embodiment, not only a small amount of precipitation but also a large amount of precipitation can be accurately sensed through a change in the width of the sensing electrode, and operation reliability can be improved accordingly.

In addition, according to the embodiment, the surfaces facing each other in the plurality of sensing electrodes are formed as curved surfaces, so that the sensing area can be maximized in the same sensor area.

1 is a side view showing a state in which a rain sensor is mounted on a windshield of a vehicle according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a detailed structure of the rain sensor shown in FIG. 1 .
FIG. 3 is a view showing the reaction layer shown in FIG. 2 .
4 is a plan view of a sensing electrode according to a first embodiment of the present invention.
FIG. 5 is a cross-sectional view taken along direction A of FIG. 4 .
FIG. 6 is a cross-sectional view taken along direction B of FIG. 4 .
FIG. 7 is a cross-sectional view taken in a direction C of FIG. 4 .
FIG. 8 is a view for explaining a manufacturing method of the rain sensor 20 shown in FIG. 2 .
9 is a plan view of a sensing electrode according to a second embodiment of the present invention.
10 is a plan view of a sensing electrode according to a third embodiment of the present invention.
11 is a view showing a wiper driving device according to an embodiment.
12 shows the characteristics of a carbon microcoil according to an embodiment of the present invention.
FIG. 13 is a diagram showing the configuration of the rainfall amount detecting unit 25 shown in FIG. 11 .
14 to 16 are diagrams illustrating changes in difference frequency values according to an embodiment of the present invention.
17 is a diagram showing changes in difference frequency values according to the second embodiment of the present invention.
18 is a flowchart illustrating a method of driving a wiper driving device step by step according to an embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the present embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification.

Combinations of each block in the accompanying drawings and each step in the flowchart may be performed by computer program instructions. Since these computer program instructions may be loaded into a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment may correspond to each block of the drawing or each flowchart. This will create means for performing the functions described in the step. These computer program instructions may also be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular way, such that the computer usable or computer readable memory The instructions stored in may also produce an article of manufacture containing instruction means for performing the functions described in each block of the drawing or each step of the flowchart. The computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to generate computer or other programmable data processing equipment. It is also possible that the instructions performing the processing equipment provide steps for executing the functions described in each block of the drawing and each step of the flow chart.

Additionally, each block or each step may represent a module, segment or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative embodiments, it is possible for the functions recited in blocks or steps to occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order depending on their function.

1 is a side view showing a state in which a rain sensor is mounted on a windshield of a vehicle according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a detailed structure of the rain sensor shown in FIG. 1, and FIG. 3 is in FIG. 4 is a plan view of a sensing electrode according to the first embodiment of the present invention.

[Rain sensor structure according to the first embodiment]

Referring to Figures 1 to 4. A rain sensor 20 is mounted on the windshield 10 of the vehicle.

The rain sensor 20 is installed to face the windshield 10 of the vehicle, and detects the presence or absence of raindrops falling on the windshield 10 or a change in impedance according to the amount of the raindrops.

The rain sensor 20 forms a sensing area at a predetermined position of the windshield 10 of the vehicle, and accordingly detects information according to the state of raindrops generated within the sensing area.

Referring to FIG. 2 , the rain sensor 20 includes a substrate 21 , a sensing electrode 22 , a reaction layer 23 , a driving unit 24 and a protective layer 25 .

The rain sensor 20 as described above detects a change in impedance according to the presence or absence of raindrops falling on the windshield 10 in a certain area inside the windshield 10 of the vehicle and provides information for driving the wiper.

The substrate 21 is a base substrate on which the sensing electrode 22, the reaction layer 23, and the driver 24 are mounted.

A sensing electrode 22 is formed on the substrate 21 . The sensing electrode 22 is formed on the upper surface of the substrate 21 while being buried by the reaction layer 23 .

The sensing electrode 22 is formed in plural, and detects impedance that changes as the reaction layer 23 reacts with a material formed on the surface of the reaction layer 23 .

Preferably, the sensing electrode 22 may include a first sensing electrode of positive polarity and a second sensing electrode of negative polarity.

The reaction layer 23 is formed on the substrate 21 and fills the top surface of the substrate 21 and the sensing electrode 22 .

Preferably, the reaction layer 23 has a predetermined thickness and is formed on the substrate 21 on which the sensing electrode 22 is formed.

The reaction layer 23 is formed of a conductive material, and has a property of changing impedance according to a change in permittivity or force generated by an external material.

Preferably, the reaction layer 23 is a carbon micro coil (CMC) having a spring shape. That is, the reaction layer 23 is formed by depositing at least one of hydrocarbons, that is, acetylene, methane, propane, and benzene, on the substrate 21 through a chemical vapor deposition (CVD) process.

Alternatively, the reaction layer 23 may be prepared using a metal catalyst based on nickel or nickel-iron.

As shown in FIG. 3 , the carbon microcoil may have a shape that is not straight but curled like a pig's tail, and is an amorphous carbon fiber having a unique structure that fiber materials cannot have. In addition, the carbon micro-coils have super-elasticity that extends to a length of 10 times or more of the original coil length.

3 (a) shows carbon microcoils formed in the reaction layer 23, and (b) is a detailed view of the carbon microcoils.

The morphology of the reaction layer 23 has a 3D-helical/spiral structure, and the crystal structure is amorphous.

In other words, the reaction layer 23 as described above is formed by growing carbon fibers in a coil shape, and thus the reaction layer 23 has a cross-sectional structure in which carbon fibers are grown in a coil shape.

That is, the reaction layer 23 is formed by the force applied as a specific material contacts the surface of the windshield 10 to which the rain sensor 20 is attached, or the dielectric constant of the specific material. Impedance change occurs.

Also, the sensing electrode 22 senses the impedance change of the reaction layer 23 and transfers a sensing signal according to the impedance change to the driving unit 24 accordingly.

The driving unit 24 is formed on the lower surface of the substrate 21, detects whether or not there is rain and the amount of rainfall according to the detection signal transmitted through the sensing electrode 22, and wipes the wiper according to the detected whether or not there is rain and the amount of rainfall. Generates a control signal for controlling the operation of

That is, in general, the REAL TERM of impedance is composed of resistance, the POSITIVE IMAGINARY TERM is composed of inductance, and the NEGATIVE IMAGINARY TERM is composed of capacitance, and is composed of the sum of the resistance, inductance, and capacitance.

Therefore, like a common resistor, inductor, and capacitor, the rain sensor 20 also requires a pair of sensing electrodes 22 to detect a change in impedance occurring in the reaction layer 23. The sensing electrode 22 serves to connect the reaction layer 23 and the driving part 24 while optimizing the sensing characteristics of the reaction layer 23 .

Here, when a specific force is applied to the surface of the front glass 10 or a material having a specific permittivity comes into contact, the capacitance of the reaction layer 23 increases, and accordingly, the resistance value and the inductance value are Opposite to capacitance, it decreases.

In this case, the sensed impedance value is the sum of the resistance value, the inductance value, and the capacitance value, and accordingly, the impedance value decreases linearly according to the force applied to the surface or the degree of permittivity.

Here, the sensing electrode 22 has a structure as shown in FIG. 4 and is disposed on the substrate 21 .

The sensing electrode 22 is provided in plurality, and preferably includes a first sensing electrode having a positive (+) characteristic and a second sensing electrode having a negative (-) characteristic.

At this time, the first sensing electrode and the second sensing electrode are spaced apart from each other on the substrate 21 by a predetermined interval. Here, conventionally, the first sensing electrode and the second sensing electrode have the same shape and have a rectangular shape elongated in the vertical direction. Accordingly, the distance between the first sensing electrode and the second sensing electrode in the related art appeared to be the same in all areas.

However, the distance between the first sensing electrode and the second sensing electrode has a close relationship with the sensing characteristic of precipitation. In other words, an impedance change occurs as raindrops form between the first sensing electrode and the second sensing electrode. However, as described above, since the interval is the same in all regions, a situation in which raindrops below the first threshold value cannot be detected has occurred. In other words, when raindrops corresponding to an area smaller than the distance between the first sensing electrode and the second sensing electrode are formed on the sensor, a normal impedance change does not occur in the sensor, and accordingly, the first threshold value or less A situation arises in which a very small amount of raindrops cannot be detected.

In addition, in the conventional sensor as described above, since the distance is the same in all areas, a situation occurs in which an accurate amount of precipitation cannot be detected for raindrops equal to or greater than the second threshold value. In other words, when raindrops corresponding to an area larger than the distance between the first sensing electrode and the second sensing electrode fall on the sensor, saturation occurs in the impedance change, and accordingly, in the conventional sensor, even though the amount of precipitation changes In spite of this, the same amount of precipitation is detected.

Accordingly, in the present invention, the distance between the first sensing electrode 22 and the second sensing electrode 22 is changed as described above so that accurate precipitation can be detected not only for a very small amount of raindrops but also for a large amount of raindrops. do.

The first sensing electrode 22 and the second sensing electrode 22 may have the same shape as each other. Preferably, the first sensing electrode 22 and the second sensing electrode 22 may have symmetrical shapes.

At this time, surfaces of the first sensing electrode 22 and the second sensing electrode 22 facing each other have a predetermined inclination angle with respect to the upper side. Accordingly, the width of each of the first sensing electrode 22 and the second sensing electrode 22 gradually decreases toward the lower direction.

Accordingly, the distance between the first sensing electrode 22 and the second sensing electrode 22 is narrowest at the uppermost side and widest at the lowermost side.

In other words, the distance between the first sensing electrode 22 and the second sensing electrode 22 gradually increases toward the lower side.

However, this is only one embodiment of the present invention, and it is also possible to form such that the distance between the first sensing electrode 22 and the second sensing electrode 22 gradually decreases toward the lower side.

FIG. 5 is a cross-sectional view taken along a direction A of FIG. 4 , FIG. 6 is a cross-sectional view taken along a direction B of FIG. 4 , and FIG. 7 is a cross-sectional view taken along a direction C of FIG. 4 .

Referring to FIG. 5 , upper regions of the first sensing electrode 22 and the second sensing electrode 22 may be spaced apart from each other by a first distance W1. Accordingly, according to the present invention, it is possible to accurately detect the amount of precipitation for a very small amount of raindrops R by the first interval W1 of the upper region.

Referring to FIG. 6 , central regions of the first sensing electrode 22 and the second sensing electrode 22 may be spaced apart from each other by a second distance W2 . Here, the second interval W2 is preferably larger than the first interval W1. Accordingly, according to the present invention, it is possible to accurately detect the amount of precipitation for an appropriate amount of raindrops R by the second interval W2 of the central area.

Referring to FIG. 7 , lower regions of the first sensing electrode 22 and the second sensing electrode 22 may be spaced apart from each other by a third distance W3. Here, the third interval W3 is preferably larger than the first and second intervals W1 and W2. Accordingly, according to the present invention, it is possible to accurately detect the amount of precipitation for a large amount of raindrops R by the third interval W3 of the lower region.

Meanwhile, in the above, although the width of each of the first sensing electrode 22 and the second sensing electrode 22 changes from the upper side to the lower side, any one of the first sensing electrode 22 and the second sensing electrode 22 Only one may have a width change, and the other may have the same width in all areas without a width change.

For example, the first sensing electrode 22 may have a trapezoidal shape in which the width gradually increases from top to bottom, and the second sensing electrode 22 may have a rectangular shape in which the width does not change in all areas. can In this case, since the first sensing electrode 22 has a trapezoidal shape, the distance between the first sensing electrode 22 and the second sensing electrode 22 gradually increases in the downward direction.

Meanwhile, the first sensing electrode 22 and the second sensing electrode 22 are connected to the driving unit 24 .

That is, the driving unit 24 includes an analog front end (AFE), to which the sensing electrodes 22 (preferably, first sensing electrodes and second sensing electrodes) are connected.

At this time, the AFE performs a differential amplification function. Depending on whether the differential amplification is positive or negative amplification, there is a difference in the state of impedance change according to the occurrence of the rain.

Therefore, the driving unit 24 detects the change state of the impedance value based on the reference value according to the differential amplification state, and drives the wiper to remove raindrops when the degree of change exceeds the threshold value do.

Hereinafter, the driving step of the wiper will be described in more detail.

That is, when raindrops fall, the raindrops have a certain force on the front glass 10 or cause a change in dielectric constant.

In addition, an impedance change occurs in the reaction layer 23 according to the applied force or the change in permittivity.

In this case, the amount of change in the impedance may correspond to whether or not the rainfall occurs and the amount of rainfall. That is, the force or permittivity applied to the reaction layer 23 increases in proportion to the amount of rainfall, and the amount of impedance change decreases in inverse proportion to the increase in permittivity or force.

As described above, when the rainfall occurs, an impedance change of the reaction layer 23 occurs, and an amplitude change of the internal clock of the driving unit 24 occurs according to the impedance change.

In addition, a differential signal according to the differential amplification of the AFE of the driver 24 is output according to the amplitude change of the internal clock.

Then, when the differential signal is output, the output differential signal is converted into a digital signal and transmitted to the main control unit of the vehicle (to be described later).

The main control unit (not shown) determines whether or not there is rain and the amount of rainfall based on the amount of impedance change according to the transmitted digital signal, and when the rainfall occurs and the corresponding rainfall exceeds a critical point, a wiper for removing raindrops activate

FIG. 8 is a view for explaining a manufacturing method of the rain sensor 20 shown in FIG. 2 .

Referring to FIG. 8 , first, a liquid 81 for forming the reaction layer 23 in a plating bath 80 is prepared.

The liquid 81 may be made of carbon micro coils. At this time, the liquid 81 may include only carbon micro coils, and differently, a resin and a dispersant may be further added.

As described above, in the first step, the carbon micro coil material and the resin are added and mixed in the plating bath 80, and the dispersant is additionally added and dispersed accordingly. The dispersing agent is for evenly dispersing the liquid on the substrate 21 later.

Next, a substrate 21 is prepared, and a sensing electrode 22 is formed on the prepared substrate 21 .

The sensing electrodes 22 are formed in plurality and have a planar structure as shown in FIG. 4 .

Next, a frame 82 is formed at the edge of the substrate 21 . The frame 82 is formed on the substrate 21 while covering the edge area of the substrate 21 and exposing the central area of the substrate 21 .

Next, the prepared liquid 81 is injected into the frame 82 of the substrate 21 .

Then, the reaction layer 23 is formed based on the injected liquid 81 through the course of the process.

At this time, the curing process may be performed for 30 minutes at a temperature of 120 ℃.

Hereinafter, the driving principle of the rain sensor 20 will be described in more detail.

As described above, the sensing electrode 22 is buried in the reaction layer 23 made of carbon microcoils. And, the sensing electrode 22 is connected to the driver 24 mounted on the lower part of the substrate 21 .

At this time, the reaction layer 23 itself can determine whether or not there is rainfall and the amount of rainfall according to the amount of impedance change, and its measurement sensitivity also varies depending on the shape of the sensing electrode 22 . Accordingly, in the embodiment, the sensing electrode 22 having the above planar shape is formed.

Therefore, in the embodiment, it is important to optimize various factors such as the composition by adjusting the content ratio of the carbon microcoils, the optimized electrode shape, and the mounting position of the driver 24.

In addition, as described above, the impedance is composed of a real part and an imaginary part, and the imaginary part is composed of a positive inductive part and a negative capacitive part, including the carbon fine coil. The rain sensor 20 to measure using two characteristic changes of the positive imaginary part (inductive) and negative imaginary part (capacitive).

That is, when it rains, the force applied to the windshield 10 of the vehicle changes according to the amount of rain, and the amount of water (raindrops) existing on the windshield 10 also changes.

At this time, the carbon micro coil (CMC:Carbon Micro Coil), as its name suggests, consists of a group of very fine coils, and is also a dielectric with a dielectric constant.

At this time, the force is measured through a change in the inductive component, that is, a change in the characteristics of the carbon fine coil, and the amount of water present on the windshield 10 is measured by a capacitive change due to a change in dielectric constant.

That is, each layer constituting the rain sensor 20 serves as a dielectric having a specific dielectric constant. If it rains as described above, a new dielectric called water exists from the electrode's point of view, resulting in a capacitive change ..

At this time, the real part can be adjusted according to the area of the reaction layer 23, and when it rains, the impedance value changes due to the change in inductive and capacitive values as described above.

Therefore, in the embodiment, whether or not it rains and the amount of rain are determined by detecting a change in the impedance value according to a change in the inductive and capacitive values of the rain sensor 20 as described above.

On the other hand, the rain sensor 20 as described above forms an adhesive member (not shown) such as silicon on the inside of the windshield 10, and is mounted on a specific inner region of the windshield 10 by the adhesive member. do.

At this time, the rain sensor 20 detects the change in impedance considering the dielectric constant of the adhesive member.

[Sensing electrode of the second embodiment]

9 is a plan view of a sensing electrode according to a second embodiment of the present invention.

Referring to FIG. 9 , the sensing electrodes 22A according to the second embodiment have curved surfaces that face each other.

Accordingly, the width of the first sensing electrode gradually decreases from the top to the bottom, the width gradually increases again from the first point, the width gradually decreases again from the second point, and the width decreases again from the third point. this gradually increases.

In addition, the width of the second electrode gradually increases from the top to the bottom, the width gradually decreases again from the first point, the width gradually increases from the second point, and the width gradually increases again from the third point. will decrease

As described above, since the sensing electrode according to the second embodiment of the present invention is formed to have a curved side surface, the sensing area can be maximized in the same sensor area, and thus the sensor sensing ability can be improved.

[Sensing electrode of the third embodiment]

10 is a plan view of a sensing electrode according to a third embodiment of the present invention.

Referring to FIG. 10 , the sensing electrode 22B according to the third embodiment may include a plurality of branch electrodes.

That is, the first sensing electrode includes a first body 221 extending in a first direction (preferably, the Y-axis direction) and a plurality of branch electrodes protruding from the first body 221 toward the second sensing electrode. (222, 223, 224).

In addition, the second sensing electrode includes a second body 225 extending in the first direction, and a plurality of branch electrodes 226 and 227 protruding from the second body 225 toward the first sensing electrode. do.

Here, the plurality of branch electrodes constituting the first sensing electrode include a first branch electrode 222, a second branch electrode 223, and a third branch electrode 224 spaced apart from each other by a predetermined distance.

Also, the plurality of branch electrodes constituting the second sensing electrode include a fourth branch electrode 226 and a fifth branch electrode 227 .

At this time, the fourth branch electrode 226 is disposed between the first branch electrode 222 and the second branch electrode 223, and the fifth branch electrode 227 is the second branch electrode 223 and It is disposed between the third branch electrodes 224 .

In this case, the respective branch electrodes are spaced apart at regular intervals, and the separation intervals may gradually change.

In other words, the first branch electrode 222 and the fourth branch electrode 226 may be spaced apart by a first distance W1, and the fourth branch electrode 226 and the second branch electrode 223 may be They may be spaced apart by a second distance W2 greater than the first distance W1. Also, the second branch electrode 223 and the fifth branch electrode 227 may be spaced apart by a third distance W3 greater than the first distance W1 and the second distance W2. In addition, the fifth branch electrode 227 and the third branch electrode 224 are spaced apart by a fourth distance W4 greater than the first distance W1, the second distance W2, and the third distance W3. can

In the third embodiment of the present invention, the minimum size and maximum size of the raindrop detection area can be adjusted through the distance between the plurality of branch electrodes, and thus the sensing ability can be improved.

[Wiper drive device]

11 is a view showing a wiper driving device according to an embodiment.

Referring to FIG. 11 , a sensor unit 20, a rainfall amount detection unit 25, a memory 30, a wiper 40, a motor 50, a wiper driving unit 60, and a control unit 70 are included.

The sensor unit 20 refers to the rain sensor, and detects a change in impedance that occurs depending on whether or not the rain falls.

The sensor unit 20 has a structure as shown in FIG. 2 .

In particular, the sensor unit 20 may have a circuit structure in which a carbon microcoil and a capacitor are connected in parallel.

The rainfall detection unit 25 is connected to the sensor unit 20 and generates an oscillation frequency according to a change in impedance of the sensor unit 20 that occurs according to whether or not there is rain and the amount of rainfall, and the difference between the oscillation frequency and the reference frequency. Determine whether or not it rains and the amount of rainfall.

At this time, the rainfall detection unit 25 detects whether the difference frequency between the oscillation frequency and the reference frequency belongs within a predetermined filtering area, and only when the difference frequency exists within the predetermined filtering area, the difference frequency Outputs the corresponding digital value.

The detailed configuration and operation of the rainfall amount sensor 25 will be described in more detail below.

Information for controlling various components of the vehicle is stored in the memory 30 .

In particular, the memory 30 stores wiper driving condition information for driving the wiper in response to the digital value according to the difference frequency output through the rainfall amount sensor 25 .

The driving condition information may include whether the wiper is driven and information on the driving speed of the wiper accordingly.

At this time, the driving condition information may be classified according to the type of filter included in the rainfall amount sensor 25 .

That is, one of a low-pass filter (LPF) and a band-pass filter (BPF) may be included in the rain sensor 25 according to the characteristics of the sensor unit 20 .

Also, the low-pass filter and the band-pass filter have different filtering frequency ranges.

Accordingly, in the embodiment, the driving condition information of the wiper corresponding to the output value according to the type of the filter included in the rainfall amount detection unit 25 is stored in the memory 30 .

The wiper 40 is mounted on the outside of the windshield 10 of the vehicle and removes moisture such as raindrops present on the windshield 10 .

The motor 50 drives the wiper 40 according to preset conditions.

The wiper driver 60 provides condition information for driving the wiper 40 to the motor 50 .

The condition information may be information on driving power to be supplied to the wiper 40 through the motor 50 .

The control unit 70 receives an output value output through the rainfall amount detecting unit 25 and sets driving conditions for driving the wiper 40 based on the received output value.

Hereinafter, the configuration and operation of the rainfall amount detection unit 25 will be described in more detail.

12 shows the characteristics of a carbon microcoil according to an embodiment of the present invention.

As shown in FIG. 12 , the carbon micro coil normally has a first inductance value, and the inductance value decreases as force or permittivity is applied to the carbon micro coil.

The inductance value has different reduction amounts depending on the type of material placed on the carbon microcoil.

That is, the inductance value has a relatively small amount of decrease when rainwater due to rainfall contacts the carbon microcoil, and has a higher decrease amount than when rainwater contacts when a part of the human body such as a person contacts, When the material is in contact, it has a higher reduction amount than when the rainwater or the human body is in contact.

FIG. 13 is a diagram showing the configuration of the rainfall amount detecting unit 25 shown in FIG. 11 .

Referring to FIG. 13 , the rainfall sensor 25 includes a first frequency generator 251, a second frequency generator 252, a difference frequency generator 253, a filter 245, and an analog-to-digital converter 255. .

The first frequency generator 251 is connected to the sensor unit 20 and generates a first frequency according to a change in impedance of the sensor unit 20 .

The first frequency generator 251 may be composed of an LC oscillation circuit.

Preferably, the first frequency generator 251 is configured to generate an oscillation frequency that changes by a change in an inductance value of the carbon micro coil using a carbon micro coil constituting the sensor unit 20 and a capacitor. do.

That is, the first frequency generator 251 oscillates the oscillation frequency of the sensor unit 20 using a carbon micro coil attached to the windshield.

In other words, the oscillation frequency of the first frequency generator 251 is determined by the inductance value of the carbon micro coil constituting the sensor unit 20 and the capacitance value of the capacitor.

The second frequency generator 252 may be a reference oscillator and generates a second frequency corresponding to the reference oscillation frequency.

At this time, the first frequency generated by the first frequency generator 251 may have a minute change. Accordingly, in the first embodiment of the present invention, the filter 245 is configured as a low-pass filter.

In the following description, it is assumed that the filter 245 is configured as a low-pass filter.

At this time, in a state where no rainfall occurs in the sensor unit 20, the first frequency generated by the first frequency generator 251 and the second frequency generated by the second frequency generator 252 have the same value. can be set to

Also, when rainfall occurs in the sensor unit 20, a difference between the first frequency and the second frequency increases according to the amount of rainfall, and the amount of rainfall can be determined based on the increasing difference value.

At this time, assuming that the inductance of the carbon microcoil included in the sensor unit 20 is L and the capacitance of the capacitor is C, the first frequency ω0 generated by the first frequency generator 251 is obtained from Equation 1 same.

Also, the first voltage value V0 corresponding to the first frequency generated by the first frequency generator 251 is expressed in Equation 2 below.

In addition, the second voltage value Vr corresponding to the second frequency generated by the second frequency generator 252 is expressed in Equation 3 below.

The difference frequency generator 253 is connected to the first frequency generator 251 and the second frequency generator 252, and the first frequency generated by the first frequency generator 251 and the second frequency generator 252 ) outputs a difference value corresponding to the difference between the second frequencies generated in ).

At this time, the difference value (Vdmod) generated by the difference frequency generator 253 is expressed in Equation 4 below.

Here, the reason why the difference value has the same value as Equation 4 is that when rain does not occur in the sensor unit 20, the first frequency generated by the first frequency generator 251 and the This is because the second frequencies generated by the second frequency generator 252 have the same value.

The filter 245 filters the output value generated from the difference frequency generator 253 and outputs the filtered output value.

At this time, the filter 245 has a filtering area corresponding to a frequency range of a certain size, and the output value of the difference frequency generator 253 is filtered within the filtering area.

Here, the filtering area may be determined by the type of the filter 245 and the change characteristics of the carbon microcoil appearing when rain occurs in the sensor unit 20 .

The change characteristics of the carbon microcoils will be described in more detail below.

Meanwhile, the type of filter 245 may be determined by the structure of the carbon micro coil.

That is, the inductance value of the carbon microcoil does not change within a large range depending on whether or not it rains and the amount of rainfall, but changes minutely, and the first frequency generated by the first frequency generator 251 according to the minutely changing value If there is no significant difference from the second frequency generated by the second frequency generator 252, the filter 245 may be configured as a low-pass filter.

And, when the first frequency generated from the first frequency generator 251 has a large difference from the second frequency generated from the second frequency generator 252 according to the change in the inductance value of the carbon microcoil. The filter 245 may be configured as a band pass filter.

In other words, the type of filter 245 may be determined by a structure such as an area of a carbon microcoil constituting the sensor unit 20 .

The analog-to-digital converter 255 converts the output value output through the filter 245 into a digital value and outputs it.

14 to 16 are diagrams illustrating changes in difference frequency values according to an embodiment of the present invention.

Referring to FIG. 14, when a specific material does not contact the sensor unit 20 and the permittivity change does not occur, the first frequency generated by the first frequency generator 251 and the second frequency generator ( The second frequency generated in 252) may have the same frequency.

Accordingly, an output value filtered by the filter 245 according to an output value output from the difference frequency generator 253 in a state in which the rainfall does not occur is approximately a DC voltage level.

And, referring to FIG. 15, when a specific material contacts the sensor unit 20 and a change in permittivity occurs, and the contact material is rainwater caused by rainfall, the output value filtered by the filter 245 is preset. A frequency shift occurs within the filtering region.

In other words, when the inductance value of the carbon micro coil of the sensor unit 20 is changed as rain occurs, the first frequency generated by the first frequency generator 251 is changed. A difference between the first frequency and the second frequency exists.

At this time, the difference frequency between the first frequency and the second frequency increases according to the intensity (rainfall amount) of the generated rainfall.

Accordingly, in an embodiment of the present invention, the amount of rainfall may be determined according to a difference frequency value between the first frequency and the second frequency. In other words, in the embodiment of the present invention, whether or not it rains and the amount of rain is determined according to the amount of change in the frequency domain according to the signal output from the filter 245.

Here, the difference between the first frequency and the second frequency may be caused by rainwater or moisture caused by rainfall, or may be caused by other foreign substances.

The foreign material may include a human body, paper, stone, and metal material.

Here, the degree of change in inductance value due to rain and the degree of change in inductance value caused by foreign substances such as the human body, paper, stone, and metal material are different from each other in the carbon micro coil.

In other words, the critical point of the change in the inductance value of the carbon microcoil is different from the critical point of the change caused by the human body, paper, stone, metal, and the like.

Accordingly, it is possible to distinguish whether the difference between the first frequency and the second frequency is caused by rain or foreign matter according to the change threshold point of the inductance value (change characteristic of the carbon microcoil).

In an embodiment, a filtering area of the filter 245 is determined according to the change characteristics of the carbon microcoil generated by each material, and a difference between the first frequency and the second frequency is determined within the determined filtering area. It is possible to selectively drive the wiper only when a

Referring to FIG. 16 , when the difference between the first frequency and the second frequency is caused by a foreign substance rather than the rain, the difference frequency may have a frequency outside the filtering area of the filter 245 .

At this time, since the difference frequency is not included in the filtering area as shown in FIG. 16, the wiper is not driven in this case.

17 is a diagram showing changes in difference frequency values according to the second embodiment of the present invention.

Referring to FIG. 17, in the design of the sensor unit 20, a difference exists between the first frequency and the second frequency when there is no rainfall, and the degree of increase or decrease of the first frequency when the rainfall occurs. When is large, the filter 245 may be configured as a band pass filter.

In this case, the filtering region of the filter 245 may have a frequency range different from that of the low-pass filter.

In addition, it is possible to determine whether or not it rains and the amount of rainfall within the filtering area according to the degree of movement of the difference frequency generated according to the change of the difference frequency.

At this time, when the filter 245 is a band pass filter, the output value of the difference frequency generator 253 is as shown in Equation 5 below.

18 is a flowchart illustrating a method of driving a wiper driving device step by step according to an embodiment of the present invention.

Referring to FIG. 18 , first, the first frequency generator 251 generates a first frequency according to the inductance value of the carbon micro coil constituting the sensor unit 20 (step 10).

Then, the second frequency generator 252 generates a second frequency corresponding to the preset reference oscillation frequency (step 11).

Next, the difference frequency generator 253 receives the first frequency generated by the first frequency generator 251 and the second frequency generated by the second frequency generator 252, and thus receives the first frequency and the second frequency. Outputs the difference frequency of the 2 frequencies (step 12).

Accordingly, the filter 245 filters the output difference frequency and determines whether the difference frequency exists within a preset filtering area (step 13).

And, if the difference frequency exists within a predetermined filtering range, the analog-to-digital converter 255 generates and outputs an output value corresponding to the difference frequency. Then, the control unit receives the output value, and detects whether or not it rains and the corresponding amount of rainfall based on the received output value (Step 14).

Subsequently, the control unit determines driving conditions of the wipers based on the detected amount of rainfall, and controls the driving of the wipers according to the determined driving conditions (step 15).

Meanwhile, if the received difference frequency does not exist within a preset filtering range, the filter 245 does not output an output value corresponding to the received difference frequency, and thus ignores the received difference frequency (16). step).

That is, when a difference between the first frequency and the second frequency is caused by a foreign substance, the difference frequency does not exist within the filtering area, and thus the rain sensor does not react.

According to the embodiment, when rain occurs, the driver's convenience can be improved by reacting immediately to the occurrence of rain and driving the wiper under driving conditions according to the amount of rain.

In addition, according to the embodiment, it is possible to provide a rain sensor with differentiated characteristics (response characteristics, precision, accuracy, power consumption, miniaturization, etc.) compared to the existing optical method by determining whether or not there is rainfall and amount of rainfall using a carbon micro coil can

In addition, according to the embodiment, since the external environment does not affect the rain sensor, an additional correction sensor for correcting the characteristics of the rain sensor is unnecessary, and thus costs can be reduced.

In addition, according to the embodiment, since it is possible to measure whether or not it rains and the amount of rainfall even with a slight change in the inductance of the carbon microcoil, it is possible to detect low-level rainfall and set a reaction area to avoid foreign matter by foreign matter A situation in which the wiper is driven can be prevented in advance.

According to the embodiment, when rain occurs, the driver's convenience can be improved by reacting immediately to the occurrence of rain and driving the wiper under driving conditions according to the amount of rain.

In addition, according to the embodiment, it is possible to provide a rain sensor with differentiated characteristics (response characteristics, precision, accuracy, power consumption, miniaturization, etc.) compared to the existing optical method by determining whether or not there is rainfall and amount of rainfall using a carbon micro coil can

In addition, according to the embodiment, since the external environment does not affect the rain sensor, an additional correction sensor for correcting the characteristics of the rain sensor is unnecessary, and thus costs can be reduced.

In addition, according to the embodiment, not only a small amount of precipitation but also a large amount of precipitation can be accurately sensed through a change in the width of the sensing electrode, and operation reliability can be improved accordingly.

In addition, according to the embodiment, the surfaces facing each other in the plurality of sensing electrodes are formed as curved surfaces, so that the sensing area can be maximized in the same sensor area.

10: windshield
20: sensor unit
21: substrate
22: sensing electrode
23: reaction layer
24: driving unit
25: protective layer
25: rainfall sensor
30: memory
40: wiper
50: motor
60: wiper driving unit
70: control unit

Claims (20)

Board;
a first sensing electrode disposed on the substrate;
a second sensing electrode disposed on the substrate and spaced apart from the first sensing electrode; and
A reaction layer disposed on the substrate and covering the first sensing electrode and the second sensing electrode and including a carbon micro coil,
The first sensing electrode includes a first side surface,
The second sensing electrode includes a second side surface facing the first side surface,
The separation distance between the first side and the second side changes in the first direction,
The first sensing electrode and the second sensing electrode are disposed extending in the first direction on the substrate,
Each width of the first sensing electrode and the second sensing electrode increases or decreases in the first direction;
The first sensing electrode and the second sensing electrode have mutually symmetrical shapes, the rain sensor. Board;
a first sensing electrode disposed on the substrate;
a second sensing electrode disposed on the substrate and spaced apart from the first sensing electrode; and
A reaction layer disposed on the substrate and covering the first sensing electrode and the second sensing electrode and including a carbon micro coil,
The first sensing electrode includes a first side surface of a curved surface, and the second sensing electrode includes a second side surface of a curved surface facing the first side surface;
The separation distance between the first side and the second side changes in the first direction,
Each of the first sensing electrode and the second sensing electrode includes an area in which a width increases in the first direction and an area in which a width decreases in the first direction. According to claim 1 or 2,
The impedance characteristics of the reaction layer change in response to a change in at least one of a force and a dielectric constant caused by rain or not,
The first and second sensing electrodes output sensing signals according to changes in the impedance characteristics of the reaction layer.
rain sensor. According to claim 3,
a driver disposed under the substrate, connected to the first and second sensing electrodes, and processing the output sensing signal; and
Further comprising a protective layer disposed surrounding the substrate, the driving unit and the reaction layer, the rain sensor. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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