JP6037560B2 - Water drop detection device and water drop removal device - Google Patents

Description

  The present invention relates to a water droplet detection device that detects water droplets attached to glass and a water droplet removal device that includes the water droplet detection device.

  For example, Patent Document 1 describes a water droplet detection device mounted on a window glass of a vehicle. The water droplet detection device includes a light emitting means for irradiating light with an incident angle of about 45 degrees to the window glass, a light receiving means for receiving light reflected from the window glass with a reflection angle of about 45 degrees, Control means for receiving the output of the light receiving means is provided. The control unit compares the output of the light receiving unit with a threshold value for driving the rain sensor or the anti-fogging sensor, and drives the wiper driving device or the air conditioner according to the comparison result.

JP 2007-33153 A

When the water droplet detection device as described above is mounted on the window glass of a vehicle, it is necessary to downsize the water droplet detection device so as not to obstruct the driver's visual field.
However, since the conventional water droplet detection device detects a change in light amount (reduced light amount) due to scattering of light due to adhesion of the water droplet, in order to increase the light amount change and improve the detection accuracy of the water droplet, In addition, it is necessary to irradiate light with an incident angle of 45 degrees or more, and it is necessary to lengthen the optical path length to some extent. For this reason, there is a problem that the distance between the light emitting means and the light receiving means becomes long, and the apparatus cannot be sufficiently downsized.

  Therefore, the present invention intends to provide a water droplet detection device capable of solving the above-described problems of the prior art and a water droplet removal device equipped with this water droplet detection device.

In order to solve the above problems, the water droplet detection device of the present invention is:
A light-emitting member that makes the pulsed light substantially perpendicularly incident on the reflecting member provided on the inner surface of the glass;
A reference light receiving member that receives pulsed light that is substantially vertically reflected from the reflecting member; and
A detection light-receiving member that receives pulsed light reflected substantially vertically from the glass;
A phase comparison unit that compares the phases of the output signals of the reference light receiving member and the detection light receiving member,
The presence or absence of water droplets on the inner surface or outer surface of the glass is detected from the result of the phase comparison unit.

The water droplet detection device of the present invention has a further preferable feature as follows:
“The reference light receiving member and the detection light receiving member are arranged at the same distance from the light emitting member and at the same distance from the glass”,
“A first shielding member that prevents the detection light receiving member from receiving the pulsed light reflected from the reflecting member is provided.”
“A second shielding member that prevents the reference light receiving member from receiving the pulsed light reflected from the glass is provided.”
“The light emitting member is arranged closer to the glass side than the reference light receiving member and the detection light receiving member”,
"The light receiving axis of the detection light receiving member and the light receiving axis of the reference light receiving member are substantially perpendicular to the glass surface",
including.

Further, the water droplet removal device of the present invention comprises the water droplet detection device, a wiper drive device, and an air conditioner,
When the water droplet detection device detects that there are water droplets on the outer surface of the glass, the wiper driving device operates,
When the water droplet detection device detects that there is a water droplet on the inner surface of the glass, the air conditioner operates.

  The water droplet detection device of the present invention can downsize the entire water droplet detection device.

1 is a block diagram of a water droplet detection device according to a first embodiment of the present invention. The detection principle of the water droplet detection apparatus according to the first embodiment of the present invention is shown, (a) is the path of pulsed light when there are water droplets on the inner surface of the glass, (b) is the signal of (a) It is explanatory drawing. The detection principle of the water droplet detection apparatus according to the first embodiment of the present invention is shown, (a) is the path of pulsed light when there are water droplets on the outer surface of the glass, (b) is the signal of (a) It is explanatory drawing. The detection principle of the water droplet detection apparatus according to the first embodiment of the present invention is shown, (a) is a path of pulsed light when there is no water droplet on the glass, (b) is a signal explanatory diagram of (a). is there. It is a flowchart of the water droplet detection apparatus which concerns on the 1st Example of this invention. The detection principle of the water droplet detection apparatus according to the second embodiment of the present invention is shown, (a) is the path of pulsed light when there are water droplets on the inner surface of the glass, (b) is the signal of (a) It is explanatory drawing.

  Hereinafter, embodiments of the present invention will be exemplarily described based on the drawings.

(First embodiment)
An embodiment of the present invention will be described with reference to FIGS.
A water droplet detection device 1 according to this embodiment is fixed to the inner surface of a windshield 2 of a vehicle. The installation location of the water droplet detection device 1 is not particularly limited, but a position that does not hinder the driver's field of view is preferable. For example, there is a periphery of the mounting base of the room mirror.

When the water droplet detection device 1 detects that there are water droplets on the inner surface 3 of the glass, an air conditioner (not shown) which is a water droplet removing device provided in the vehicle operates, and the air conditioner removes water droplets on the inner surface of the glass. Remove.
When the water droplet detection device 1 detects that there are water droplets on the outer surface 4 of the glass, a wiper driving device (not shown), which is a water droplet removing device provided on the outer surface 4 of the glass, operates. Remove water droplets on the outer surface.

  The water droplet detection apparatus 1 of this example includes a light emitting member 10, a reference light receiving member 20, a detection light receiving member 30, a first shielding member 40, a second shielding member 50, a phase comparison unit 60, and a microcomputer 70. .

  The light emitting member 10 is a unit in which pulsed light is substantially perpendicularly incident on a reflecting member 11 provided on an inner surface 3 of glass. The light emitting member 10 is made of a light emitting diode, for example, and irradiates the glass 2 with pulsed light. A driving signal is input to the light emitting member 10 from the driving circuit 12, and the driving signal S1 of the light emitting member has an amplitude V1 = 3 Vp-p, a period T1 = 0.5 s, a pulse, as shown in FIG. The pulse waveform has a width T1P = 0.25 s.

  As shown in FIG. 1, the light emitting member 10 is disposed between the reference light receiving member 20 and the detection light receiving member 30, and the reference light receiving member 20 and the detection light receiving member 30 are arranged at the same distance from the light emitting member 10. And at the same distance from the inner surface 3 of the glass. In order to reduce the size of the water droplet detection device 1, it is preferable that the reference light receiving member 20 and the detection light receiving member 30 are arranged close to the light emitting member 10.

  Further, the light emitting member 10 has a high directivity for irradiating pulsed light only on the glass 2 side (in this example, with a spread angle of less than 30 degrees from the irradiation axis (vertical direction in FIG. 2) of the light emitting member 10). In addition, since the pulsed light is not directly incident on the reference light receiving member 20 and the detection light receiving member 30, they are arranged closer to the glass 2 side than the positions of the reference light receiving member 20 and the detection light receiving member 30.

On the inner surface 3 of the glass of this example, the reflecting member 11 arranged in parallel with the inner surface 3 of the glass is slightly deviated from the irradiation axis of the light emitting member 10 (in this example, on the right side from the irradiation axis of FIG. 2). ) Is provided. The reflecting member 11 is formed of, for example, a reflecting film deposited with aluminum, and the pulsed light of the light emitting member 10 is incident on the reflecting film surface in a substantially vertical direction, and reflects the pulsed light with high efficiency.
In this specification, “substantially normal incidence” refers to an incident angle of 0 to 10 degrees with respect to the reflective film surface or the glass surface.
The thickness of the reflective film (vertical direction in FIG. 2) is smaller than the distance between the light emitting member 10 and the inner surface 3 of the glass or the thickness H of the glass 2 (vertical direction in FIG. 2). Is almost negligible.

The reference light receiving member 20 is made of a photodiode, for example. The pulsed light emitted from the light emitting member 10 is reflected almost vertically by the reflecting member 11 and enters the reference light receiving member 20, whereby an output signal corresponding to the received pulsed light is obtained. That is, the output signal does not appear when the pulsed light is not incident, and the predetermined output signal appears when the pulsed light is incident.
As shown in FIG. 2B, the output signal S2 of the reference light receiving member of this example has an amplitude V2 = a phase delayed by θ1 in accordance with the moving distance of the pulsed light as compared with the driving signal S1 of the light emitting member. The pulse waveform is 0.5 Vp-p, cycle T1 = 0.5 s, and pulse width T1P = 0.25 s. The phase of the output signal S2 of the reference light receiving member is set as a reference phase with respect to an output signal S3 of the detection light receiving member 30 described later.

  The detection light receiving member 30 receives pulsed light reflected from the glass 2 in a substantially vertical direction. The detection light receiving member 30 is made of, for example, a photodiode, and an output signal corresponding to the received pulsed light is obtained. That is, the output signal does not appear when the pulsed light is not incident, and the predetermined output signal appears when the pulsed light is incident.

  For example, when water droplets 5 adhere to the inner surface 3 of the glass, as shown in FIG. 2A, the pulsed light emitted from the light emitting member 10 is irregularly reflected on the inner surface 3 of the glass and detected. The light enters the light receiving member 30. Then, as shown in FIG. 2B, for example, the output signal S3 of the detection light receiving member is in phase with the output signal S2 of the reference light receiving member (that is, the phase is delayed by θ1 compared to the drive signal S1 of the light emitting member). And a pulse waveform having an amplitude V3 = 0.3 Vp-p, a period T1 = 0.5 s, and a pulse width T1P = 0.25 s.

  When water droplets 5 are attached to the outer surface 4 of the glass, as shown in FIG. 3A, the pulsed light emitted from the light emitting member is irregularly reflected on the outer surface 4 of the glass and detected and received. Incident on the member 30. Then, as shown in FIG. 3B, for example, the output signal S3 of the detection light receiving member is delayed in phase by θ2 by two times the glass thickness H compared to the output signal S2 of the reference light receiving member (that is, As compared with the drive signal S1 of the light emitting member, the phase is delayed by (θ1 + θ2)), the amplitude V3 = 0.3Vp−p, the period T1 = 0.5s, and the pulse width T1P = 0.25s.

  Further, when water droplets 5 are not attached to the inner surface 3 and the outer surface 4 of the glass, the pulsed light emitted from the light emitting member 10 is emitted from the light emitting member 10 to the glass as shown in FIG. Although it progresses to 2, it is hardly reflected from the glass 2. Then, no pulsed light is incident on the detection light receiving member 30, and the output signal S3 of the detection light receiving member does not appear as shown in FIG.

  The light receiving axis of the detection light receiving member 30 and the light receiving axis of the reference light receiving member 20 are preferably formed substantially perpendicular to the surface of the glass 2 so that the reflected light can be received most efficiently.

  The first shielding member 40 prevents the detection light receiving member 30 from receiving the pulsed light reflected from the reflecting member 11, and is provided between the light emitting member 10 and the detection light receiving member 30. The first shielding member 40 of this example is formed by a shielding plate provided between the light emitting member 10 and the detection light receiving member 30, and may be formed by a shielding cylinder covering the outer periphery of the detection light receiving member 30.

  The second shielding member 50 prevents the reference light receiving member 20 from receiving the pulsed light reflected from the glass 2, and is provided between the light emitting member 10 and the reference light receiving member 20. The second shielding member 50 of this example is formed by a shielding plate provided between the light emitting member 10 and the reference light receiving member 20, and may be formed by a shielding cylinder that covers the outer periphery of the reference light receiving member 20.

  The phase comparison unit 60 compares the phase of the output signal S2 of the reference light receiving member with the phase of the output signal S3 of the detection light receiving member. The phase comparison unit 60 receives the output signal S2 of the reference light receiving member and the output signal S3 of the detection light receiving member. The phase comparison unit 60 detects the detection light receiving member with reference to the phase of the output signal S2 of the reference light receiving member. The degree of phase delay of the output signal S3 is output.

Specifically, the phase comparison unit 60 of this example is configured by an exclusive OR logic operation circuit (not shown), and when the output signal S2 and the output signal S3 are in phase, “low” is output. In other cases, “high” is output. In this example, the result is as follows.
First, when the water droplet 5 is attached to the inner surface 3 of the glass, the phase of the output signal S2 and the output signal S3 is the same as shown in FIG. All remain “low”.
Further, when water droplets 5 are attached to the outer surface 4 of the glass, the phase of the output signal S3 is delayed by θ2 from the output signal S2 as shown in FIG. In the output signal S4, a pulse waveform having a pulse width T2P appears, and this pulse width T2P is equal to the phase difference (θ2) between the output signal S2 and the output signal S3.
Further, when water droplets 5 are not attached to the inner surface 3 and the outer surface 4 of the glass, as shown in FIG. 4B, there is no output signal S3, so the output signal S4 of the phase comparison unit 60 is A pulse waveform having a pulse width T3P appears, and this pulse width T3P is equal to the pulse width T1P of the output signal S2.
The output signal S4 of the phase comparison unit 60 is input to the microcomputer 70.

  The microcomputer 70 detects the presence or absence of water droplets on the inner or outer surface of the glass using the output signal of the phase comparison unit 60. The output of the microcomputer 70 is input to a wiper driving device or an air conditioner that is a water droplet removing device, and the microcomputer 70 can start or stop the wiper driving device or the air conditioning device.

  Next, the water droplet detection routine will be described with reference to the flowchart of FIG.

[Water drop detection routine]
First, the microcomputer 70 outputs a signal to be input to the light emitting member 10. The light emitting member 10 emits pulsed light, and the reference light receiving member 20 receives pulsed light reflected from the reflecting member 11 in a substantially vertical direction. Then, the microcomputer 70 makes the following determination using the output signal of the phase comparison unit 60 and the drive signal S1 of the light emitting member.
Specifically, as shown in FIG. 4B, when the pulse width T1P of the output waveform S2 of the reference light receiving member and the pulse width T3P of the output waveform S4 of the phase comparison unit are the same, the microcomputer 70 Detect the absence of water droplets on the surface and the outer surface.
In cases other than the above determination, the microcomputer 70 detects the presence of water droplets on the inner or outer surface of the glass (S101 to S103).

When it is detected that there is a water droplet on the inner surface or the outer surface of the glass 2, the microcomputer 70 makes the following determination.
As shown in FIG. 2B, when the output signal of the phase comparator 60 does not appear, the microcomputer 70 detects the presence of the water droplet 5 on the inner surface 3 of the glass and outputs an air conditioner operation signal. The air conditioner removes water droplets.
Further, as shown in FIG. 3B, when the output signal of the phase comparison unit 60 appears, the microcomputer 70 detects the presence of the water droplet 5 on the outer surface 4 of the glass, and outputs the wiper driving device operation signal. The wiper drive device outputs the water droplets (S104 to S106).

  As described above, in this example, the light emitting member 10 that makes the pulsed light substantially perpendicularly incident on the reflecting member 11 provided on the inner surface 3 of the glass, and the reference light receiving member 20 that receives the pulsed light reflected almost vertically from the reflecting member 11, A detection light receiving member 30 that receives pulsed light reflected from the glass 2 in a substantially vertical direction, and a phase comparison unit 60 that compares the phases of the output signals of the reference light receiving member 20 and the detection light receiving member 30 are provided. In this example, the presence or absence of water droplets on the inner surface or outer surface of the glass 2 is detected from the output result of the phase comparison unit 60.

Therefore, this example has a phase comparison unit that compares the phases of the output signals of the reference light-receiving member and the detection light-receiving member, so that the light-emitting member can be substantially perpendicularly incident on the glass or the reflecting member. Therefore, in this example, unlike the conventional example, it is not necessary to separate the light emitting unit and the light receiving unit, the reference light receiving member and the detection light receiving member can be brought close to the light emitting member, and the entire water droplet detection device can be greatly reduced in size. .
That is, in the configuration as in the conventional example, it is necessary to irradiate the window glass with light having an incident angle of 45 degrees or more in order to improve the detection accuracy of water droplets, and the distance between the light receiving means and the light emitting means cannot be shortened. The water droplet detector could not be downsized.
On the other hand, this example has a phase comparison unit that compares the phases of the output signals of the reference light receiving member and the detection light receiving member, so that the detection accuracy can be improved because the phase that does not change depending on the amount of light is compared. As a result, the reference light-receiving member and the detection light-receiving member can be disposed close to the light-emitting member, and the entire water droplet detection device can be greatly reduced in size.

Further, in the configuration as in the conventional example, it is necessary to lengthen the optical path length to some extent in order to improve the detection accuracy of water droplets, and the light emitting means and the light receiving means cannot be arranged close to the glass surface.
On the other hand, in this example, since the phase comparison unit that compares the phases of the output signals of the reference light receiving member and the detection light receiving member is provided, water drops on the inner surface or the outer surface of the glass even if the water drop detection device is arranged close to the glass surface. By being able to detect the presence / absence of a water droplet by the phase difference, the water droplet detection device can shorten the installation distance with respect to the glass surface. Therefore, in this example, in combination with the downsizing of the entire water droplet detection device, the water droplet detection device can be mounted on the glass surface very compactly.

Moreover, in this example, by providing the reflecting member 11 on the inner surface 3 of the glass, it is possible to reliably detect the presence or absence of water droplets on the inner surface and the outer surface of the glass.
That is, when the reflecting member 11 is provided on the outer surface 4 of the glass, when a water droplet adheres to the inner surface or the outer surface of the glass, the output signal S2 of the reference light receiving member and the output signal S3 of the detection light receiving member become the same signal, The presence or absence of water droplets on the inner or outer surface of the glass cannot be detected.
Specifically, when a water droplet adheres to the outer surface of the glass, the output signal S3 of the detection light receiving member is in phase with the output signal S2 of the reference light receiving member. Further, even when a water droplet adheres to the inner surface of the glass, it is reflected by the water droplet adhered to the inner surface of the glass corresponding to the reflecting member 11, and the output signal S3 of the detection light receiving member is the output signal S2 of the reference light receiving member. Be in phase. Therefore, in this case, even if the output of the phase comparison unit 60 is detected, the presence or absence of water droplets on the inner surface or the outer surface of the glass cannot be detected.
On the other hand, in this example, when the reflection member 11 is provided on the inner surface 3 of the glass, and the water droplet 5 is attached to the inner surface 3 of the glass, the output signal S3 of the detection light receiving member is the output of the reference light receiving member. When the water phase 5 is in phase with the signal S2 and the water droplet 5 is attached to the outer surface 4 of the glass, the output signal S3 of the detection light receiving member is twice the thickness of the glass as compared with the output signal S2 of the reference light receiving member 20. Appears out of phase. Therefore, in this example, the presence or absence of water droplets on the inner surface and the outer surface of the glass can be reliably detected from the output result of the phase comparison unit.

Further, the reference light receiving member 20 and the detection light receiving member 30 are arranged at an equal distance from the light emitting member 10 and at an equal distance from the glass 2.
Therefore, by simply comparing the phase of the output signal S2 of the reference light receiving member with the phase of the output signal S3 of the detection light receiving member, the microcomputer 70 can detect the water droplets on the outer surface or inner surface of the glass. Presence / absence can be easily detected, the apparatus is simplified, and the manufacturing cost is reduced.
Specifically, when there is a water drop on the inner surface of the glass, the microcomputer uses the fact that the phase of the output signal S3 of the detection light receiving member is in phase with the phase of the output signal S2 of the reference light receiving member. Outputs that there are water droplets on the inner surface. Further, when there is a water drop on the outer surface of the glass, the phase of the output signal S3 of the detection light receiving member is delayed from the phase of the output signal S2 of the reference light receiving member (the phase is delayed by twice the thickness H of the glass). Then, the microcomputer outputs that there are water droplets on the outer surface of the glass. Therefore, by simply comparing the phases of the output signals of the reference light-receiving member and the detection light-receiving member, it is possible to easily detect the presence or absence of water droplets on the outer surface or inner surface of the glass, simplifying the apparatus and reducing the manufacturing cost. .

Further, a first shielding member 40 that prevents the detection light receiving member 30 from receiving the pulsed light reflected from the reflecting member 11 is provided.
Therefore, the detection light receiving member is less susceptible to the influence of the pulsed light reflected from the reflecting member, so that erroneous detection can be reduced.
In particular, in the case of this example, the pulsed light incident on the reference light receiving member is stronger than the pulsed light incident on the detection light receiving member (because the amplitude value is large). The influence of light can be reliably reduced and false detection can be reduced.

In addition, a second shielding member 50 that prevents the reference light receiving member 20 from receiving the pulsed light reflected from the glass 2 is provided.
Therefore, since the reference light receiving member is not easily affected by the pulsed light reflected from the glass, erroneous detection can be reduced.

  Further, the light emitting member 10 of this example is disposed closer to the glass 2 side than the reference light receiving member 20 and the detection light receiving member 30. Therefore, the pulsed light of the light emitting member 10 is less likely to be directly incident on the reference light receiving member 20 and the detection light receiving member 30, so that erroneous detection can be further reduced.

In addition, the light receiving axis of the detection light receiving member 30 and the light receiving axis of the reference light receiving member 20 in this example are formed substantially perpendicular to the glass surface.
Therefore, the reference light receiving member and the detection light receiving member can receive the reflected light from the reflecting member and the glass most efficiently, and the detection accuracy is improved.

  Further, the light emitting member 10 of this example is in contact with the first shielding member 40 and the second shielding member 50, the reference light receiving member 20 is in contact with the second shielding member 50, and the detection light receiving member 30 is the first shielding member. If it contacts 40, the water droplet detection device can be further miniaturized.

Further, the water droplet removing device includes a water droplet detecting device 1, a wiper driving device, and an air conditioner. When the water droplet detecting device detects that there are water droplets on the outer surface 4 of the glass, the wiper driving device operates to wipe the wiper. When the driving device removes water droplets on the outer surface 4 of the glass and the water droplet detection device detects that there are water droplets on the inner surface 3 of the glass, the air conditioner operates to remove the water droplets on the inner surface of the glass. .
Therefore, the water droplet removal apparatus can automatically determine whether the water droplet removal apparatus is started or stopped without manual operation by the vehicle driver. Therefore, this example can provide a water droplet removing device including a small water droplet detecting device that can automatically drive the wiper driving device and the air conditioner.

(Second Embodiment)
FIG. 6 shows the detection principle of the water droplet detection apparatus according to the second embodiment of the present invention. (A) is a path of pulsed light when there is a water droplet on the inner surface of the glass, and (b) is ( It is signal explanatory drawing of a). In FIG. 6, the same reference numerals as those in FIGS. 1 to 5 denote the same members, and a detailed description thereof will be omitted.

Although one light emitting member 10 of the first embodiment is arranged between the reference light receiving member 20 and the detection light receiving member 30, in this example, a drive signal is simultaneously input from the drive circuit 12. Two light emitting members 13 and 14 are provided. One light emitting member 13 is disposed obliquely left front of the reference light receiving member 20, and the other light emitting member 14 is disposed obliquely right forward of the detection light receiving member 30.
The one light emitting member 13 and the other light emitting member 14 are arranged close to the same distance from the inner surface 3 of the glass, and the reference light receiving member 20 and the detection light receiving member 30 are the same from the inner surface 3 of the glass. Arranged in the distance. The reference light receiving member 20 and the detection light receiving member 30 are arranged at the same distance from the one light emitting member 13 and the other light emitting member 14, respectively.
Therefore, also in this example, the reference light receiving member 20 and the detection light receiving member 30 can be brought close to the light emitting members 13 and 14, and the entire water droplet detection apparatus can be greatly reduced in size, and the phase of the output signal S2 of the reference light receiving member can be changed. By simply comparing this phase with the phase of the output signal S3 of the detection light receiving member as a reference, the microcomputer 70 can easily detect the presence or absence of water droplets on the outer surface or inner surface of the glass, and the apparatus is simplified. Manufacturing cost can be reduced.
Further, since the light emitting members 13 and 14 of this example are arranged closer to the glass 2 side than the reference light receiving member 20 and the detection light receiving member 30, the pulsed light of the light emitting members 13 and 14 is detected with the reference light receiving member 20. It becomes difficult to directly enter the light receiving member 30, and detection errors can be reduced.

In the first embodiment, the first shielding member 40 is provided between the light emitting member 10 and the detection light receiving member 30, and the second shielding member 50 is disposed between the light emitting member 10 and the reference light receiving member 20. However, one third shielding member 80 of this example is provided, and on one side (right side) of the third shielding member 80, the one light emitting member 13 and the reference light receiving member 20 are disposed. The other light emitting member 14 and the detection light receiving member 30 are arranged on the other side (left side) of the three shielding members 80.
The third shielding member 80 is arranged so that the detection light receiving element 30 does not receive the pulsed light reflected from the reflecting member 11, and the reference light receiving member 20 does not receive the pulsed light reflected from the glass 2. It is arranged in. That is, the third shielding member 80 constitutes both roles of the first shielding member 40 and the second shielding member 50 in the first embodiment as a single member.
Therefore, the detection light receiving member is less affected by the pulsed light reflected from the reflecting member, so that erroneous detection can be reduced, and the reference light receiving member is less affected by the pulsed light reflected from the glass. Detection can be reduced.

In the case of this example, a shielding member is not disposed between one light emitting member 13 and the reference light receiving member 20, and a shielding member is disposed between the other light emitting member 14 and the detection light receiving member 30. Absent.
Therefore, in this example, the reference light receiving member 20 can be disposed so as to partially overlap the one light emitting member 13 with respect to the vertical direction of the irradiation axis, and the detection light receiving member 30 can be disposed with respect to the vertical direction of the irradiation axis. Since the light emitting member 14 can be partially overlapped with the other light emitting member 14, the entire water droplet detecting device can be further downsized.

FIG. 6 illustrates the case where there are water droplets on the inner surface of the glass, and FIG. 6A shows the pulsed light emitted from the two light emitting members 13 and 14 in FIG. 6 (b) is a signal explanatory diagram similar to FIG. 2 (b).
Further, the path of the pulsed light when there are water droplets on the outer surface of the glass of this example is the path of the pulsed light when irradiated from the two light emitting members 13 and 14 in FIG. The explanatory diagram is the same as FIG.
Further, the path of the pulsed light when there is no water droplet on the inner surface and the outer surface of the glass of this example is the path of the pulsed light when irradiated from the two light emitting members 13 and 14 in FIG. The signal explanatory diagram in this case is the same as FIG.
The water droplet detection routine of this example is the same routine as that of the first embodiment.

  The two embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and the above embodiments can be appropriately modified without departing from the spirit of the present invention. is there. For example, the drive signal S1 (pulse waveform) of the light emitting member of this example may be amplitude-modulated (for example, modulation frequency 100 kHz) and irradiated by the light emitting member. In this case, output signals from the reference light receiving member and the detection light receiving member are input to a demodulating circuit (not shown), and this demodulating circuit outputs the change in amplitude, and can be handled in the same manner as the above-described embodiment.

  Further, although the above-described reference light receiving member 20 and the detection light receiving member 30 are arranged at the same distance from the glass 2, the reference light receiving member 20 and the detection light receiving member 30 may not be arranged at the same distance from the glass 2. . For example, if the detection light-receiving member is arranged away from the glass side with respect to the reference light-receiving member, the output signal S3 of the detection light-receiving member is delayed by the separated distance. Then, if the output signal S3 of the detected light receiving member is configured to advance the phase by the separated distance, this example can be handled in the same manner as the above embodiment.

DESCRIPTION OF SYMBOLS 1 Water drop detection apparatus 2 Glass 3 Glass inner surface 4 Glass outer surface 5 Water drop 10 Light emitting member 11 Reflective member 12 Drive circuit 13 One light emitting member 14 The other light emitting member 20 Reference light receiving member 30 Detection light receiving member 40 First shielding member 50 Second shielding member 60 Phase comparison unit 70 Microcomputer 80 Third shielding member H Glass thickness S1 Light emitting member drive signal S2 Reference light receiving member output signal S3 Detection light receiving member output signal S4 Phase comparison unit output signal

Claims (7)

A light-emitting member that makes the pulsed light substantially perpendicularly incident on the reflecting member provided on the inner surface of the glass;
A reference light receiving member that receives pulsed light that is substantially vertically reflected from the reflecting member; and
A detection light-receiving member that receives pulsed light reflected substantially vertically from the glass;
A phase comparison unit that compares the phases of the output signals of the reference light receiving member and the detection light receiving member,
A water droplet detection apparatus that detects the presence or absence of water droplets on the inner surface or outer surface of the glass from the result of the phase comparison unit.   The water droplet detection device according to claim 1, wherein the reference light receiving member and the detection light receiving member are disposed at the same distance from the light emitting member and at the same distance from the glass.   The water droplet detection device according to claim 1, wherein a first shielding member that prevents the detection light receiving member from receiving pulsed light reflected from the reflection member is provided.   4. The water droplet detection device according to claim 1, wherein a second shielding member that prevents the reference light receiving member from receiving pulsed light reflected from the glass is provided. 5.   5. The water droplet detection device according to claim 1, wherein the light emitting member is disposed closer to the glass side than the reference light receiving member and the detection light receiving member. 6.   6. The water droplet detection device according to claim 1, wherein a light receiving axis of the detection light receiving member and a light receiving axis of the reference light receiving member are substantially perpendicular to the glass surface. A water droplet removing device comprising the water droplet detection device according to any one of claims 1 to 6, a wiper drive device, and an air conditioner,
When the water droplet detection device detects that there are water droplets on the outer surface of the glass, the wiper driving device operates,
When the water droplet detection device detects that there are water droplets on the inner surface of the glass, the air conditioner operates.

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