JP2001264457A - Raindrop detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a raindrop detector accurately determining a rainfall condition without any erroneous determination even when foreign matter such as mud other than raindrops is stuck to a raindrop detecting area. SOLUTION: For example, the raindrop detector 20 is provided with a control circuit 27 combining a signal showing a raindrop condition from optical raindrop detection parts 29-30 and a signal showing an atmospheric pressure state from a pressure detection part (atmosphere sensor) 60 together for determining a rainfall state. In this way, for example, if a pressure detection part 60 detects a high atmospheric pressure condition and determines low possibility of a rainfall condition, adhesion of foreign matter is determined even when the raindrop detection part determines a raindrop, so that a rainfall condition can be determined more accurately. When the raindrop detector 20 is used in a wiper automatic controller, for example, wiper automatic control matching an actual rainfall condition can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raindrop detecting device for detecting a rainfall condition, and more particularly to a raindrop detecting device capable of detecting a rainfall condition without erroneously detecting foreign matter such as mud.

[0002]

2. Description of the Related Art Conventionally, as a raindrop detecting device, for example, a device applied to an automatic wiper control device of an automobile is known. This automatic wiper control device is equipped with, for example, a raindrop detection device having the following configuration. This raindrop detection device is installed on the vehicle interior side of the front windshield, and includes a light emitting element for emitting light toward the front windshield, which is an object to which raindrops are attached, and a light receiving element for receiving light reflected by the front windshield. And an optical raindrop detector.

Here, when raindrops adhere to the raindrop detection area of the front windshield that reflects and reflects light from the raindrop detector, the amount of reflected light changes due to the raindrops. The amount of changed light is detected by a light receiving element to detect raindrops, and a signal from the raindrop detection unit is received by the control unit to control the wiper blade to operate.

[0004]

However, in the prior art, even if foreign matter other than raindrops, such as mud, adheres to the raindrop detection area of the front windshield, which reflects and reflects light from the raindrop detector, it does not receive light. Element 28 senses the amount of light that has changed, and the raindrop detector is controlled to operate the wiper blade as in the case of raindrops.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a method for detecting foreign matter other than raindrops, such as muddy water, in a raindrop detection area.
It is an object of the present invention to provide a raindrop detecting device capable of accurately determining a rainfall state without erroneous determination.

[0006]

According to a first aspect of the present invention, there is provided a raindrop detecting apparatus for determining a rainfall state from both a raindrop state and an atmospheric pressure state. By complementing information (atmospheric pressure state) correlated with the rainfall state, it is possible to provide a raindrop detection device that can accurately determine the presence of raindrops.

According to the raindrop detecting device of the third aspect of the present invention, the control unit determines that it is raining when raindrops are present and the atmospheric pressure is lower than a predetermined value.

When the value of the signal from the pressure detecting section is equal to or less than a predetermined reference value, the control section determines that it is in a low pressure state and a rainfall state. This makes it possible to provide a raindrop detection device that can more accurately determine the presence of raindrops as compared to the case where it is determined whether or not it is raining only based on the detection signal of the raindrop detection unit.

According to the raindrop detecting device of the fourth aspect of the present invention, since the pressure detecting section and the raindrop detecting section are provided in the same case, it can be compactly integrated, the wiring of the pressure signal can be shortened, and the external signal noise can be reduced. The pressure signal is input to the control unit without being affected by the pressure. Therefore, it is possible to provide a raindrop detecting device capable of accurately detecting atmospheric pressure and accurately determining the presence of raindrops.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The raindrop detecting device according to the present invention relates to a raindrop detecting device for detecting the amount of rainfall adhering to, for example, a windshield of a vehicle, a ship, an aircraft or the like, or a window of a house. The present invention relates to a raindrop detecting device capable of accurately detecting a rainfall state without performing.

The above-described raindrop detecting apparatus is used in a system for moving a wiper in a windshield of an automobile or the like, and for opening and closing windows in a house.

In the following embodiments, examples in which the raindrop detecting device of the present invention is applied to an automatic wiper control device of an automobile to provide a raindrop detecting device capable of accurately detecting a rainfall state are shown in FIGS. 1 to 5.
This will be described with reference to FIG.

FIG. 1 is a block diagram showing the overall structure of an automatic wiper control device for an automobile, FIG. 2 is an operation mode table showing an example of operation modes of a wiper switch of the automatic wiper control device shown in FIG. 1, and FIG. FIG. 2 is a sectional view showing an example of the raindrop detecting device shown in FIG. FIG. 4 is a flowchart showing a control operation of the wiper driving device 10 shown in FIG.
FIG. 5 is a flowchart showing a control operation of the raindrop detecting device 20 shown in FIG.

As shown in FIG. 1, the automatic wiper control device includes a wiper driving device 10 and a raindrop detecting device 20. The wiper driving device 10 includes a wiper switch 11, a control circuit 12, a wiper motor driving circuit 13, and a communication device. A wiper motor 15 and a wiper 1
6 is driven.

As shown in FIG. 2, the wiper switch 11 is operated in one of four operating positions of stop (OFF), auto mode (AUTO), low speed operation (Lo), and high speed operation (Hi). And outputs a switch position signal to the control circuit 12 in accordance with the selection.

The operation of the control circuit 12 will now be described with reference to the flowchart shown in FIG. When the auto mode (AUTO) is selected by the operator (step 10)
0) First, the raindrop detecting device 20 is driven (step 101). Therefore, the control circuit 12 detects the presence or absence of raindrops on the front windshield 70, which is the raindrop attachment target, and the amount of the raindrops, and transmits the raindrop detection output to the communication circuit 14 by the raindrop detection device 20. Is determined (steps 102 and 103), and the wiper motor 15 is driven (step 104).

Therefore, four wiper operation modes (OFF, INT (intermittent operation), Lo, Hi) shown in FIG. 2 are selected according to the state of raindrops attached to the front windshield, and the wiping operation by the wiper 15 is automatically performed. Done in
Specifically, the wiper blade of the wiper 16 wipes the fan-shaped wiping area of the front windshield.

On the other hand, when the wiper switch 11 is not in the automatic mode, the control circuit 12 drives and controls the wiper 16 in an operation mode corresponding to a manual mode (OFF, Lo, Hi) selected by the operator. (Steps 105 to 10
9).

Next, the raindrop detecting device 20 determines whether or not raindrops have adhered to the front windshield 70, which is an object to which raindrops are attached, and detects the presence or absence of raindrops (20-30, etc.). And a control circuit 27 that is a control unit that determines a rainfall state based on a signal from the pressure detection unit 60 and a signal from a pressure detection unit 60 that detects an atmospheric pressure state.

The insolation sensor 22 shown in FIG. 1 detects the amount of insolation that differs between day and night to determine a reference value for judging raindrops in the raindrop detecting section, and the control circuit 27 judges raindrops based on a signal from the raindrop detecting section. To obtain signals from such sensors used in other systems.

The raindrop detector 20 has three functions, and the control circuit 27 controls these functions.

One is a raindrop detecting section for optically detecting the state (presence / absence and amount of raindrops) of raindrops on the front windshield 70.
It comprises a light receiving element 28, a detection circuit 29, and an amplification circuit 30. The circuits 25, 26, and 28 to 30 are supplied with power from a power supply circuit 24. When detecting a raindrop, the control circuit 27 causes a predetermined current to flow to the light emitting element 26 to emit light, and the detection signal from the light receiving element 28 is output. The signal is detected, amplified, and input to the control circuit 27.

The other is a light emitting element 26 and a light receiving element 28
It is a dew condensation preventing unit that prevents dew condensation on the surface of a prism 42 (see FIG. 3) installed therebetween, and is configured by a temperature sensor 23 that detects the temperature of the prism 42, a heater driving circuit 31, and a heater 32. The control circuit 27 includes the prism 4
The state of energization to the heater is controlled in accordance with the temperature signal of the temperature sensor 23 so that the temperature around the heater 2 becomes a predetermined temperature.

The other is to take into the control circuit 27 the detection signals of the solar radiation sensor 22 for determining the raindrop determination reference value in the raindrop detector in accordance with the amount of solar radiation and the atmospheric pressure sensor 60 for detecting atmospheric pressure. This is a wiper operation mode instructing unit that takes in a detection signal indicating the amount of received light detected by the above-described raindrop detection unit, accurately determines the rainfall state based on these three detection signals, and determines the wiper operation mode in the auto mode.

A wiper operation instruction signal instructing the wiper operation mode determined in the control circuit 27 is transmitted to the wiper driving device 10 through the communication circuit 21.

The atmospheric pressure sensor 60 is connected to the raindrop detecting device 2.
0, and the solar radiation sensor 22 uses an example of substituting the signal of this type of sensor used in another system, but the atmospheric pressure sensor 60 also uses this type of signal used in another system. Instead of the sensor signal, the solar radiation sensor 2
2 may be built in the raindrop detecting device 20.

The power supply circuit 24 is supplied with power from a battery 50 through an ignition key 51 and is distributed to the control circuit 27, the heater drive circuit 31, the light emission drive circuit 25, and the like.

Next, an outline of an example of mounting the raindrop detecting device 20 will be described with reference to FIG.

The raindrop detector 20 is adhered to the inner wall of the front windshield 70 by a transparent adhesive layer 41.

The raindrop detector of the raindrop detector 20 detects the presence or absence of raindrops. The light from the light emitting element 26 passes through the incident side convex lens 40 into the case 20a, and enters the prism 42, the transparent adhesive layer 41, and the front windshield 70. Through the trajectory of the arrow 80 and the light receiving element 2
8 to receive.

The outer wall 70 of the front windshield 70
When raindrops, mud, etc. adhere to a,
The light passing through the trajectory is scattered and absorbed, so that the amount of light received by the light receiving element 28 is smaller than when there is no attachment of raindrops or the like. The amount of decrease in the amount of light is determined relative to the amount of adhesion of raindrops or the like.

Atmospheric pressure sensor 60 for detecting atmospheric pressure state
Are arranged on a printed circuit board 44 on which the control circuit 27 and the like are mounted.

As described above, the case 2 of the raindrop detecting device 20
Since the pressure detection unit (atmospheric pressure sensor 60) is provided inside 0a, it can be integrated compactly, the wiring of the pressure signal can be shortened, and the pressure signal is sent to the control unit (control circuit 27) without being affected by external signal noise. Is entered. Therefore, it is possible to provide a raindrop detecting device capable of detecting the atmospheric pressure with high accuracy and determining the rainfall state more accurately.

Next, the operation of the raindrop detecting device 20 will be described with reference to the flowcharts shown in FIGS.

When the operator selects the wiper switch 11 in the automatic mode (AUTO), step 10 shown in FIG.
At 0 and 101, the control circuit 12 of the wiper driving device 10 performs the raindrop detecting operation on the raindrop detecting device 20 with the communication circuit 1.
An instruction is issued to the control circuit 27 through 4 and 21. As a result, the raindrop detection device 20 starts the detection operation, and the raindrop detection process shown in FIG. 5 starts.

First, a signal input process (step 201) for taking in a detection signal to the control circuit 27 is executed.
From 0, the amount of solar radiation around the vehicle from the solar radiation sensor 22,
Detection information indicating the ambient temperature of the prism 42 is acquired from the temperature sensor, and detection information indicating the atmospheric pressure is acquired from the atmospheric pressure sensor.

In step 202, a signal for detecting ambient brightness is obtained from the solar radiation sensor. A raindrop is accurately detected by switching a reference value for determining a raindrop based on a signal from the raindrop detector in accordance with the surrounding brightness.

In step 203, the heater 32 is energized so that the temperature around the prism 42 falls within a predetermined temperature range, so that the surface of the prism 42 does not dew.

Then, the front windshield 70
In order to prevent misjudgment when foreign matter such as mud adheres to the upper portion, rainy weather determination is performed which correlates with low pressure or the like rather than atmospheric pressure (step 204). Raindrop determination is performed (step 205). Here, for example, 99.5 KPa is used as the atmospheric pressure determination value correlated with rain, and when it is lower than this value, it is determined that there is a low pressure state correlated with rain.

When the precondition for raindrop determination is satisfied in step 204, a wiper operation instruction signal is selected in step 205 in accordance with the amount of light received by the raindrop detector.
The data is transmitted to the control circuit 12 through the communication circuits 21 and 14. Here, the wiper operation instruction signal is a signal indicating any one of the four wiper operation modes (OFF, INT, Lo, Hi) shown in FIG.
FF), middle → intermittent operation (INT), Akira → low speed operation (L
o), the determination value for the amount of received light is determined based on experiments or the like so as to be substantially zero or close to zero → high-speed operation (Hi).

On the other hand, even in the auto mode, step 2
When it is determined that it is not raining (high pressure) in 04,
A wiper operation instruction signal indicating stop of the wiper operation is transmitted to the control circuit 12 (step 206).

When the control circuit 12 in the wiper driving device 10 receives the wiper operation instruction signal from the control circuit 27 of the raindrop detection device 20 (step 102), the wiper operation is performed according to the instruction contained in the signal. The mode is determined (step 103), and the drive of the wiper 16 is controlled (step 104).

When the manual mode is selected instead of the automatic mode, the selected wiper operation mode (OFF, Lo, H
It operates in i), but at this time, the detecting operation of the raindrop detecting device 20 is stopped to suppress power consumption.

With the above-described configuration, it is possible to prevent a raindrop from being determined in a situation where rain cannot normally occur, such as a sunny day or a high-pressure state, and to greatly reduce an erroneous determination due to foreign matter such as mud on the front windshield 70. Can be reduced. When this is applied to the automatic wiper control device of the raindrop detecting device of the present invention, it is possible to realize a favorable automatic wiper control that matches the surrounding situation and the driving situation.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example in which a raindrop detection device according to an embodiment of the present invention is applied to an automatic wiper control device of an automobile.

FIG. 2 is an operation mode table showing an example of an operation mode of a wiper switch of the wiper control device shown in FIG.

FIG. 3 is a sectional view showing an example of the raindrop detecting device shown in FIG.

FIG. 4 is a flowchart showing an operation of the wiper control device shown in FIG. 1;

FIG. 5 is a chart showing an operation of the raindrop detecting device shown in FIG. 1;

[Explanation of symbols]

 Reference Signs List 20 raindrop detector 27 control unit 28 light receiving element 60 pressure detector (atmospheric pressure sensor) 26 light emitting element 26, 28 raindrop detector

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Kurahashi 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in Denso Co., Ltd. (Reference) 2G059 AA05 BB05 CC11 EE01 EE02 GG02 HH02 JJ11 JJ12 KK01 NN07 3D025 AA01 AC01 AC02 AD02 AG36 AG40

Claims (4)

[Claims] 1. A raindrop detecting device, wherein a rainfall state is determined from both a raindrop state and an atmospheric pressure state. 2. A raindrop detecting section for detecting the presence or absence of raindrops, a pressure detecting section for detecting a state of atmospheric pressure, and control for determining a rainfall state based on both detection signals of the raindrop detecting section and the pressure detecting section. And a raindrop detecting device. 3. The raindrop detecting device according to claim 2, wherein the control unit is configured to determine a rainfall state when raindrops are present and the atmospheric pressure is equal to or lower than a predetermined value. 4. The raindrop detecting device according to claim 2, wherein the pressure detecting section and the raindrop detecting section are provided in the same case.