KR101258411B1 - Rain sensor using receive difference of multi-path optical signal and method for detecting moisture on glass surface - Google Patents

Abstract

PURPOSE: A rain sensor using the difference of multi-directional lights and a method for detecting moisture on the surface of a windshield using the same are provided to accurately grasp the surface condition of the windshield by using the quantity variation of the light received from multiple directions, thereby improving the control reliability of a wiper. CONSTITUTION: A rain sensor using the difference of multi-directional lights comprises multiple light emitting parts(110,120), a light receiving part(130), and a control part(140). The light emitting parts are installed to radiate the light to a windshield. The light receiving part receives the light reflected from the interface of the windshield. The control part receives electrical signals from the light receiving part; calculates the quantity variation of the light successively received from each light emitting part to the light receiving part; and calculates at least one of instantaneous absolute variation and accumulated variation on the light quantity differences. [Reference numerals] (140) Control part;

Description

RAIN SENSOR USING RECEIVE DIFFERENCE OF MULTI-PATH OPTICAL SIGNAL AND METHOD FOR DETECTING MOISTURE ON GLASS SURFACE}

The present invention relates to a rain sensor using a multipath light receiving difference and a method of detecting moisture on a glass surface using the same, and more particularly, a difference in the amount of light received through a multipath formed by a plurality of light emitting units and a single light receiving unit. The present invention relates to a rain sensor using a multipath light-receiving vehicle and a method of detecting moisture on a glass surface using the same, so that the moisture state of the glass surface on the front of the vehicle can be accurately determined by using a.

In general, transparent materials such as glass impede the view when water droplets accumulate, so that the vehicle can drive a motor to wipe off water droplets or moisture on an outer surface over a large area to improve visibility through the front glass. The wiper system is installed.

Such a wiper system of the vehicle is operated by the driver to have a delay characteristic so as to operate intermittently at a selected delay interval. Recently, in order to alleviate the inconvenience of the manual operation of the wiper system, a rain sensor is installed on the glass in front of the vehicle, and thus, the wiper system can be driven and the wiping speed of the wiper according to the moisture level of the glass through the rain sensor. This allows the driver to eliminate the inconvenience of adjusting the wiper speed according to the change of the wiper operation and driving situation.

The rain sensor used in the wiper system of the vehicle may be a sensor using a conductive or capacitive sensor or a piezoelectric sensor or an optical sensor to detect a moisture condition. Is being used. These photosensors use the principle that light is deflected and diffused in its normal path by moisture present on its outer surface in the glass in front of the vehicle.

Referring to the rain sensor used in the conventional vehicle wiper system as follows.

1 is a view schematically showing a rain sensor according to the prior art, Figure 2 is a view for explaining the operation of the rain sensor according to the prior art.

As shown in FIG. 1 and FIG. 2, the rain sensor 10 according to the related art is an interface between the light emitting part 11 emitting light and the glass 20 on the front surface of the vehicle irradiated from the light emitting part 11. It includes a light receiving unit 12 for receiving the light reflected from (I), the light emitting unit 11 is used an IR LED for irradiating infrared light. Since the light incident from the light emitting part is incident on the glass (S) of the glass, that is, part of the light is transmitted or scattered by the water droplets, the light reflected from the interface (I) of the glass 20 and entering the light receiving part is bitten on the glass. There is a difference between when there is no and when there is no.

The rain sensor 10 according to the related art determines a change in the moisture state of the surface S of the glass 20 through a change in the amount of light received by the light receiver 12, and the light receiver 12 is received by the received light. The electrical signal output from the equation is expressed as Equation 1 below.

[Equation 1]

Electrical signal = IR _emitter + IR _external -IR _LOSS

Here, the IR _light emitting portion represents infrared rays as light generated by the light emitting portion, and the _outside of the IR represents the amount of infrared rays introduced from the outside. IR _Loss is The infrared rays generated by the light emitting portion indicate the amount of infrared rays not incident on the light receiving portion. The electrical signal may be a value of a current or a voltage output according to the amount of light received by the light receiver 12.

As described above, since the rain sensor 10 according to the related art is affected by infrared rays incident from the outside, the rain sensor 10 accurately determines the moisture state of the surface S of the glass 20 in front of the vehicle. Difficulties have been accompanied, and this has caused a problem of lowering the reliability of the motion control of the vehicle wiper system.

In order to solve the above problems, the present invention can accurately determine the moisture state of the glass surface on the front of the vehicle by using the change in the difference in the amount of light received through the multiple paths formed by the plurality of light emitting units and a single light receiving unit. This makes it possible to increase the reliability of the wiper motion control.

In order to solve the above problems, according to an aspect of the present invention, the rain sensor for detecting the moisture state of the glass surface, a plurality of light emitting unit is installed to irradiate light on the glass; And a light receiving unit receiving light reflected from the light emitting unit and reflected at the interface of the glass, and using the difference in the amount of light received from the light receiving unit through multiple paths from each of the light emitting units to change the state of the glass surface. There is provided a rain sensor using a multipath light receiving difference to allow grasping.

And a control unit configured to receive an electric signal from the light receiving unit, and calculate a difference change in the amount of light received sequentially from each of the light emitting units through the electric signal.

The controller calculates any one or both of the instantaneous absolute change amount and the cumulative change amount according to time with respect to the difference in the amount of light.

The light emitting unit is made of an infrared LED, and is installed to irradiate infrared light of multiple paths to the single light receiving unit.

According to another aspect of the present invention, there is provided a method for sensing a moisture state of a glass surface, the method comprising: receiving light reflected from a plurality of light emitting parts and reflected at an interface of the glass; And calculating a difference change in the amount of light sequentially received from the light receiving units through multiple paths from each of the light emitting units.

The step of calculating the difference change in the amount of light is to calculate any one or both of the instantaneous absolute change amount and the cumulative change amount over time for the difference in the amount of light.

The method may further include determining a state of the glass surface by changing the difference in the amount of light.

The present invention can accurately grasp the glass surface state of the front of the vehicle by using the change in the amount of light received through the multiple paths formed by the plurality of light emitting units and a single light receiving unit, thereby increasing the reliability of the wiper operation control. have.

1 is a view schematically showing a rain sensor according to the prior art.
2 is a view for explaining the operation of the rain sensor according to the prior art.
3 is a block diagram illustrating a rain sensor using a multipath light reception difference according to an embodiment of the present invention.
4 is a configuration diagram illustrating an operation of a rain sensor using a multipath light reception difference according to an embodiment of the present invention.
5 is a flowchart illustrating a method of detecting moisture on a glass surface according to another embodiment of the present invention.

Since the present invention can have various embodiments by various modifications, specific embodiments will be described in detail with reference to the drawings. This particular embodiment does not limit the invention.

3 is a block diagram showing a rain sensor using a multi-path light receiving difference according to an embodiment of the present invention, Figure 4 is an operation of the rain sensor using a multi-path light receiving difference according to an embodiment of the present invention. It is a schematic diagram for demonstrating.

3 and 4, the rain sensor 100 using the multipath light receiving difference according to an embodiment of the present invention is for detecting a moisture state of the surface S ′ of the glass 200. The light emitting units 110 and 120 and the light receiving unit 130 may be included.

The light emitting units 110 and 120 are provided in a plurality so as to irradiate light onto the glass 200. In the present embodiment, the light emitting units 110 and 120 may be provided in two, but the light emitting units 110 and 120 may be three or more. The light emitting units 110 and 120 may be formed of, for example, infrared LEDs for irradiating infrared rays, and various light emitting elements for irradiating light other than infrared rays may be used, and to irradiate infrared rays of multiple paths to a single light receiving unit 130. Each can be installed.

The light receiver 130 receives light reflected from the light emitters 110 and 120 and reflected at the interface I ′ of the glass 200. Light incident on the glass 200 is partially transmitted or scattered by water droplets R such as rain water present on the surface S ′ of the glass 200. Therefore, the amount of light incident on the light receiving part due to the presence or absence of water droplets on the surface S 'of the glass 200 is different.

By forming multiple optical paths in a small area by the plurality of light emitting units 110 and 120, it is possible to use a change in the difference of optical signals received and converted through each path. That is, the light receiving unit 130 may determine the state of the surface S 'of the glass 200 by using a change in the amount of light sequentially received from each of the light emitting units 110 and 120 through multiple paths. In addition, the light receiving unit 130 may be a photo diode (Photo diode) for converting the light energy into electrical energy, for example.

The light emitting units 110 and 120 and the light receiving unit 130 may be installed in the main body 150 having a material or structure through which light may be transmitted to the glass 200 on the front surface of the vehicle. Installed on the printed circuit board 151 may be made of a module. The body 150 may be attached to the inner surface of the glass 200 by the bonding portion 152 having an adhesive component.

The controller 140 may further include a controller 140 for receiving an electric signal from the light receiver 130 and calculating a change in the difference in the amount of light.

The control unit 140 receives an electric signal corresponding to the intensity of light received from the light receiving unit 130, and sequentially receives the light receiving unit 130 from each of the light emitting units 110 and 120 through the electric signal, for example, a current value or a voltage value. The difference in the amount of light received is calculated. The controller 140 may calculate any one or both of the instantaneous absolute change amount and the cumulative change amount with respect to the difference in the amount of light. Here, the instantaneous absolute change amount may correspond to the static change amount, and the cumulative change amount for a predetermined time may correspond to the dynamic change amount.

The controller 140 may be implemented as an electronic circuit or a circuit device on the printed circuit board 151 in the main body 150, or may be implemented as an electronic circuit or a circuit device separate from the main body 150. In addition, the controller 140 controls each of the light emitting units 110 and 120 to generate an optical signal with a parallax, and not only calculates a difference change in the amount of light generated by each light emitting unit, but also calculates a difference change in the calculated amount of light. It can be provided as a signal for controlling the operation of a wiper system.

5 is a flowchart illustrating a method of detecting moisture on a glass surface according to another embodiment of the present invention.

Referring to FIG. 5, in the method for detecting moisture on a glass surface according to another embodiment of the present invention, light reflected from the interface I of the glass 200 by the light emitting units 110 and 120 is reflected on the light receiving unit 130. Comprising a step (S11) to be received, and a step (S12) for calculating the difference change in the amount of light sequentially received by the light receiving unit 130 through the multi-path from each of the light emitting unit (110,120).

In the calculating of the difference change in the amount of light (S12), one or both of the instantaneous absolute change amount and the cumulative change amount over time with respect to the difference in light amount may be calculated in parallel, and the process may be performed by the controller 140. Can be done.

On the other hand, the step (S13) to determine the state of the surface of the glass 200 on the front of the vehicle through the change in the amount of light calculated from the step of calculating the difference in the amount of light (S12).

The operation of the rain sensor using the multi-path light receiving difference according to the present invention and the method of detecting the moisture on the glass surface using the same will be described in more detail.

Referring to FIG. 4, according to the rain sensor using a multipath light reception difference and a method of detecting moisture on a glass surface using the same, the light is radiated from the light emitting units 110 and 120 to a single light receiving unit 130 by multiple paths. Through the change in the received amount of light received, it can be determined as the change in the moisture state of the surface (S ') of the glass 200, the light receiving unit based on any one light emitting unit 110 ("light emitting unit 1") When the electric signal 1 output from the 130 is expressed as an equation, it is expressed as [Equation 2], and the electric power output from the light receiving unit 130 on the basis of the other light emitting unit 120 ("light emitting unit 2"). If signal 2 is expressed by an equation, Equation 3 is obtained.

&Quot; (2) "

Electrical signal 1 = IR _{light emitter 1} + IR _external

&Quot; (3) "

Electrical signal 2 = IR _{light emitter 2} + IR _external

In this case, the IR _{light emitting unit 1} and the IR _light emitting unit 2 represent infrared rays as light generated by the light emitting unit 1110 and the light emitting unit 2 120 and incident on the light receiving unit 130, and the _outside of the IR light receiving unit 130 from the outside. Infrared light is incident on (). In addition, the electrical signal 1 and the electrical signal 2 may be a current value or a voltage value output by the light receiving unit 130 according to the amount of light received.

[Equation 2] and [Equation 3], the change in the amount of light sequentially received by the light receiving unit 130 through the multi-path from each of the light emitting unit (110, 120) (electric signal 1-electrical signal 2) by the formula Expressed in Equation 4 below.

&Quot; (4) "

Electric signal 1-Electric signal 2 = IR _{light emitter 1} -IR _{light emitter 2}

As such, the light of each of the plurality of light emitting devices 110 and 120 is received by the light receiving unit 130 through the multipath, so that an IR _external component that requires filtering in a process of obtaining a difference between the electrical signals output from the light receiving unit 130 is obtained. Is removed, and further, by using any one or both of the instantaneous absolute change amount and the cumulative change amount over time for the difference in the amount of light, it is possible to increase the accuracy of the determination of the moisture state on the surface (S ') of the glass 200. have. Therefore, the amount of change in the multipath signal difference is determined by the degree of change in the position of the water film irregularly formed on the surface S 'of the glass 200 in front of the vehicle and an object capable of reflecting light close to the surface S' of the glass 200. The speed of the wiper can be determined using the degree of change over time.

Referring to FIG. 6, when the light receiving unit d includes three light emitting units a, b and c with respect to a single light receiving unit d, the light receiving unit d reaches from each of the light emitting units a, b and c. When light is input to the light receiving portion d through three light paths A, B, and C, structurally, these paths A, B, and C can be designed almost similarly, so that each path A, The magnitude of the signal received through B, C) may be similar. For example, if the magnitude of the signal input through the A path is 10, the magnitude of the signal input through the B path or the C path will also be about 10. When the difference of the signal for this is obtained, Equation 5 below.

[Equation 5]

In this case, IR _A , IR _B , and IR _C represent the magnitudes of the optical signals incident to the light receiving units through the A, B, and C paths, respectively.

In this case, it is not exactly the same, but a value close to zero can be obtained. However, even if the absolute value change amount before obtaining such a difference becomes large, the result is the same. In addition, even if the value is near 100 instead of near 10, the difference between the signals becomes a small value close to zero. Therefore, judging the absolute signal change amount in parallel also makes it possible to accurately determine the moisture state of the surface S 'of the glass 200. For example, the first time you start a car on a sunny day, if the amount of light received from each path (A, B, C) is around 100, in a cloudy weather with fog or frost on the windshield, The value of degree will be read. However, if we only look at the difference between the signals, in both cases the value is close to zero. In this case, it is difficult to judge only the value of the difference in order to make the wiper operate, so the instantaneous absolute change amount is used.

In addition, the water droplets or foreign matters formed on the glass in front of the vehicle showing only a fixed amount of change. However, water droplets and foreign matters formed on the glass in front of the running vehicle become active and affect the amount of light received by the light emitting unit. In fact, even if there is no rain and the water is condensed, if the movement increases a lot, the change of the value occurs severely. This makes it possible to operate by wiping the speed of the wiper using the difference in cumulative change over time, ie the difference in dynamic change.

In addition, when the droplets increase and the frequency of the droplets collide with the glass surface increases, the difference in the amount of change also changes rapidly on the time axis. This change is irregular but the amount of change in the difference changes quickly. This can be used to determine exactly how much rain is present and how it is going.

In the case of rain, the change in the amount of received light converges to the minimum or maximum value and varies within these ranges. By converting the degree, the wiper can be operated.

In this way, since the light may be dominantly influenced by the change amount of the difference rather than the absolute value of the received light amount, and all the incoming light is removed in the process of obtaining the light reception difference of the multipath, By using the amount of change generated in the process of the irradiated light is received in the light receiving unit, it is possible to accurately grasp the moisture state on the glass surface of the front of the vehicle, thereby increasing the reliability of the wiper operation control.

Although the present invention has been described with reference to the accompanying drawings, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should be defined not only by the claims, but also by those equivalent to the claims.

110,120 light emitting unit 130 light receiving unit
140: control unit 150: main body
151: printed circuit board 152: junction

Claims (7)

In the rain sensor for detecting the moisture state of the glass surface,
A plurality of light emitting parts provided to irradiate the glass with light;
A light receiving unit which receives the light generated from the light emitting unit and reflected at the interface of the glass; And
Receives an electrical signal from the light receiving unit, and calculates the change in the difference in the amount of light received from the light receiving unit sequentially from each of the light emitting unit through the electrical signal, from the instantaneous absolute change amount and the cumulative change over time And a control unit for calculating any one or all of them,
Rain sensor using a multipath light reception difference, characterized in that to determine the state of the glass surface by using the change in the difference in the amount of light. delete delete The method of claim 1,
The light emitting unit is an infrared LED, the rain sensor using a multi-path light receiving difference, characterized in that each installed to irradiate a multi-path infrared light to the single light receiving unit. In the method of detecting the moisture state of the glass surface,
Irradiating light emitted from a plurality of light emitting parts to be reflected at an interface of the glass to receive a light receiving part; And
Calculating one or both of an instantaneous absolute change amount and a cumulative change amount over time with respect to a difference in the amount of light sequentially received from the light receiving parts through the multi-paths from each of the light emitting parts. How to detect moisture. delete The method of claim 5, wherein
And detecting the state of the glass surface by changing the difference in the amount of light.

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