JP2014133423A - Raindrop detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a raindrop device capable of resolving visual troublesomeness of a user.SOLUTION: A rain sensor 3 equipped with a microcomputer 40 detecting the amount of raindrops adhered to an outer surface of a window glass 1 and controlling a wiper device 2 according to the amount of the raindrops, is provided with raindrop detecting means 20 for detecting reflection light amount from the raindrops W adhered to the outer surface of the window glass 1, and imaging means 30 for imaging the raindrops W adhered to the outer surface of the window glass 1. The microcomputer 40 sets wiping characteristics according to the amount of the raindrops, and adjusts the wiping characteristics so as to increase the wiping performance of the wiping device 2 as compared with a case that a raindrop diameter r is large, when a raindrop diameter r of the imaged raindrops W is small. Therefore, the wiper device 2 can be controlled according to the raindrop diameter r which is an attribute of the raindrop W drawing the attention of a user.

Description

  The present invention relates to a raindrop detection device that detects the amount of raindrops attached to a window glass, and more particularly to a raindrop detection device that controls a wiper device in accordance with the detected amount of raindrops.

Conventionally, a raindrop detection device that detects the amount of raindrops attached to the outer surface of the window glass has been provided, and the operation mode such as the wiper speed and intermittent time of the wiper device is automatically controlled according to the amount of raindrops detected by this raindrop detection device. What to do is known.
The raindrop detection apparatus of Patent Document 1 includes a raindrop sensor that outputs a detection signal corresponding to the amount of raindrops attached to the outer surface of the window glass, a change amount calculation means that calculates a change amount of the detection signal of the raindrop sensor, and raindrops attached The difference calculation means for calculating the difference between the detection signal of the raindrop sensor and the detection signal of the raindrop sensor when not, and the lower limit value that the raindrop sensor can output when the change amount is decreasing and the difference is increasing A discriminating means for discriminating the maximum amount of raindrops is provided.

  The raindrop sensor of this raindrop detection device is a light-receiving element (photodiode) in which the projected light is totally reflected from the outer boundary surface between the windglass and the external space when no raindrop is attached to the detection area on the outer surface of the windglass. ). In addition, when raindrops are attached to the detection area on the outer surface of the windshield, some of the light projected on the part corresponding to the raindrops is transmitted because it passes through the windglass and the raindrops attached to it. Of the light, only the reflected light that does not pass through the window glass and raindrops is received by the light receiving element. That is, in this raindrop detection means, the detection signal increases as the amount of raindrops attached to the outer surface of the window glass decreases, and the detection signal decreases as the amount of raindrops attached to the outer surface of the window glass increases.

  Normally, this type of raindrop detection device is set as an optional device that can be arbitrarily selected by the user. Moreover, in the car maker, the same raindrop detection apparatus is used not only for one vehicle type but also for other vehicle types. Therefore, the wiper control device includes a wiper drive device and a raindrop detection device, and the raindrop detection device is often provided with a wiper control unit that controls the wiper drive device.

Japanese Patent No. 4777860

Since the raindrop detection device of Patent Document 1 can be determined as the maximum raindrop amount exceeding the lower limit value that can be output by the raindrop sensor when the change amount of the change amount calculation means tends to decrease and the difference of the difference calculation means tends to increase, The detection range of the raindrop detection device can be expanded, and the maximum raindrop amount can be determined.
However, in the technique of Patent Document 1, the wiping ability is uniformly increased when the amount of raindrops is large compared to when the amount of raindrops is small, even though there are various attributes of raindrops such as raindrop diameter. ing.
Therefore, even if the user feels that wiping is unnecessary, the wind glass is wiped when the amount of raindrops is large, and even if the user feels that wiping is necessary, the window glass is not wiped when the amount of raindrops is small. There is a possibility that it cannot be resolved sufficiently.

From the viewpoint of brain physiology, it is known that when a stimulus having characteristics different from the surrounding stimulus exists in the visual field, the stimulus is noticeable (pops out) and has a characteristic that attracts the user's attention. . Therefore, the present inventor conducted an experiment to change the raindrop attribute and verify the raindrop adhesion rate when the user starts the operation of the wiper device.
In the first verification experiment, a plurality of types of raindrops (diameters 1.5 to 3.0 mm) having different diameters were prepared, and the raindrop adhesion rate (%) at which the user started wiping the raindrops attached to the wind glass with the wiper device (Hereinafter referred to as wiping timing) was measured. Note that the deposition rate of raindrops is constant (20.0 / sec).
In the second verification experiment, a plurality of types of raindrops (attachment speed 6.0 to 35.0 / sec) having different attachment speeds were prepared, and the wiping timing by the user was measured. The raindrop diameter is constant (diameter 2.3 mm).

As shown in FIG. 14, it was recognized that when the deposition speed of raindrops is constant, when the raindrop diameter is small, the wiping timing by the user is earlier than when the raindrop diameter is large.
As shown by the solid line in FIG. 15, when the raindrop diameter is constant during the daytime, it has been recognized that when the raindrop adhesion speed is low, the wiping timing by the user is earlier than when the raindrop adhesion speed is high. Further, as shown by the broken line in FIG. 15, the wiping timing is generally faster at night than in the daytime, but when the raindrop deposition speed is low, the wiping timing by the user is earlier than when the raindrop deposition speed is high, The trend was similar to the daytime measurement results.

According to the above verification experiment, even when the raindrop adhesion rate is the same, if there are many raindrops with small diameters, the user pays attention to each raindrop, and thus feels bothered visually, and the attention dispersion It is presumed that the raindrops are erased by wiping to solve the problem.
Also, when the raindrop adhesion speed is high, the user's attention to the individual raindrops cannot catch up with the raindrop adhesion speed, so the visual annoyance felt by the user is reduced and the wiping timing by the user is delayed. It is guessed.
In other words, it is known that the timing of wiping raindrops by the user is not determined simply by a decrease in forward visibility due to raindrops, but rather by the attributes of raindrops that attract the user's attention, the so-called raindrop diameter and raindrop adhesion speed. It was done.

  The objective of this invention is providing the raindrop detection apparatus which can eliminate a user's visual troublesomeness.

  The raindrop detection apparatus according to claim 1, wherein the raindrop detection apparatus includes a control unit that detects a raindrop amount attached to an outer surface of the window glass and controls a wiper device according to the raindrop amount. The control means is characterized in that when the picked-up raindrop diameter is small, the wiper device has a higher wiping capability than when the raindrop diameter is large.

  In the raindrop detection apparatus according to the first aspect of the present invention, since the image pickup means for picking up the raindrops adhering to the outer surface of the window glass is provided, the raindrop diameter, which is one of the main factors that give the user visual inconvenience, is detected. be able to.

  According to a second aspect of the present invention, in the first aspect of the present invention, there is provided an adhesion rate measuring unit for measuring an adhesion rate of raindrops adhering to the outer surface of the window glass, and the control means has a high adhesion rate when the adhesion rate is low. The wiper device is characterized in that the wiping capability of the wiper device is increased.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, there is provided first optical means for irradiating the inner surface of the window glass with light and detecting reflected light reflected by the window glass. A raindrop amount detection unit for detecting the amount of raindrops based on the output is provided in the control means.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, there is provided second optical means for irradiating the inner surface of the window glass with light and detecting reflected light reflected by raindrops attached to the window glass. (2) A raindrop amount detector for detecting a raindrop amount based on the output of the two optical means is provided in the control means.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the wiper device is configured so that at least one of a wiping speed and an intermittent period can be changed.

  According to the first aspect of the present invention, it is possible to detect the raindrop diameter, which is one of the main factors that cause visual inconvenience to the user. Therefore, it is possible to detect the raindrop diameter of the raindrops adhering to the window glass. When the diameter is small, the wiping ability of the wiper device can be made higher than when the raindrop diameter is large, thereby effectively eliminating the user's visual troublesomeness.

  According to the second aspect of the present invention, it is possible to detect the deposition speed of raindrops, which is one of the main factors that give the user visual annoyance. Therefore, when the deposition speed is low, the deposition speed is high. In comparison, the wiping ability of the wiper device can be increased, and the visual annoyance of the user can be more effectively eliminated.

According to invention of Claim 3, the amount of raindrops can be detected accurately based on the reflected light reflected by the window glass.
According to the invention of claim 4, it is possible to accurately detect the amount of raindrops based on the reflected light reflected by the raindrops attached to the window glass.

  According to the invention of claim 5, the forward visibility of the user can be kept good irrespective of the raindrop attribute.

It is a block diagram of the communication system of the motor vehicle based on Example 1 of this invention. It is the figure which looked at the vehicle body front from the vehicle interior. It is a control circuit diagram which shows the electrical structure which concerns on a wiper apparatus, a rain sensor, and a wiper switch. It is a perspective view of a rain sensor. It is a block diagram which shows the whole structure of a rain sensor. It is explanatory drawing which shows the raindrop detection principle of a wind glass. It is a graph which shows the correlation with a raindrop adhesion rate and the output of a raindrop detection means. It is a wiping speed map at the time of auto mode control. It is an intermittent time map at the time of auto mode control. It is a flowchart which shows the process sequence which concerns on a wiper control process. 5 is a perspective view of a rain sensor according to Embodiment 2. FIG. It is a block diagram which shows the whole structure of a rain sensor. It is explanatory drawing which shows the raindrop detection principle of a wind glass. It is a figure which shows the wiping timing according to raindrop diameter. It is a figure which shows the wiping timing according to raindrop adhesion speed.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

Embodiment 1 of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, in this embodiment, a front window glass (hereinafter referred to as a window glass) 1, a wiper blade (not shown) for wiping raindrops and dirt adhering to the outer surface of the window glass 1, a wiper motor 2 a, etc. As an example, a description will be given of a vehicle V including a wiper device 2 configured by the above, a rain sensor 3 (raindrop detection device), and the like.

First, a basic communication system of the automobile V will be described.
As shown in FIG. 1, an automobile V includes a body control module (hereinafter referred to as BCM) 4, an engine control module (hereinafter referred to as ECM) 5, a brake control mechanism 6, and a head. A light control mechanism (Adaptive Front-Lighting System: AFS) 7 and the like are provided, and these control mechanisms 4 to 7 are connected to each other by a CAN (Controller Area Network) 8 so as to be able to transmit and receive each other.

As shown in FIG. 3, the BCM 4 is configured to be capable of comprehensive control of a plurality of devices such as the wiper device 2 (wiper motor 2 a) and the rain sensor 3, and includes a microcomputer (hereinafter referred to as a microcomputer) 9 and a first relay circuit 10. And a second relay circuit 11 and the like.
When the first relay circuit 10 is turned on and the second relay circuit 11 is turned off, the wiper motor 2a is driven at a low speed, and when the first relay circuit 10 is turned off and the second relay circuit 11 is turned on, the wiper motor 2a is driven at high speed.

  The microcomputer 9 is output from a CPU that performs control processing and arithmetic processing, a read-only memory (ROM) for storing various data such as various programs and control coefficients, each control mechanism 4 to 7 and a plurality of sensors. A memory (RAM) in which various data can be written, a power supply circuit, and the like (not shown). The microcomputer 9 converts a control signal from the microcomputer 40 described later and transmits the control signal to the wiper device 2.

The ECM 5 is configured to be able to control an engine ignition mechanism, a fuel injection device, an intake / exhaust system, a valve mechanism, start control, and the like based on a plurality of sensor outputs (all not shown).
The brake control mechanism 6 is configured to be able to control a mechanism (Antilock Brake System) that avoids a collision while applying a sudden brake and a mechanism (Dynamic Stability Control) that prevents understeer and oversteer during vehicle turning (any one) (Not shown).
The AFS 7 is configured such that the direction of a headlight (not shown) formed to be tiltable can be changed to a direction suitable for the traveling direction of the traveling vehicle V based on the steering angle and the vehicle speed.

As shown in FIG. 1, the CAN 8 connects the control mechanisms 4 to 7 via a CAN bus 8a so that multiplex communication is possible, and performs bus access control by a multi-master method in which data is transmitted in units of frames (not shown). In each frame, an arbitration ID and a vehicle ID corresponding to the type of the automobile V are set in advance for each frame. The smaller the arbitration ID, the higher the priority for flowing the frame to the CAN bus 8a.
Communication signals output from the control mechanisms 4 to 7 and various sensors are stored in the data field of the frame and transmitted to the respective transmission destinations via the CAN bus 8a.

Next, the wiper device 2 will be described.
As shown in FIG. 3, the wiper device 2 includes a wiper blade, a wiper arm (not shown), a wiper motor 2a, an automatic stop switch 2b, etc., and each of them is manually operated by the user on the wiper switch 12 (see FIG. 2). The mode control is configured to be executable.
The auto stop switch 2b is a rotation maintaining circuit, and when the user turns off the wiper switch 12, if the wiper blade has not reached the lower reverse position (stop position), the current supply to the wiper motor 2a is continued. Then, the wiper blade is stopped at the stop position.

As shown in FIG. 2, the wiper switch 12 is provided on a side portion of the steering 13 and is configured to be movable in stages in the vertical direction. As shown in FIG. 3, the wiper switch 12 is manually operated to change the electrical connection to the OFF position 12a, the MIST position 12b, the AUTO position 12c, the LOW position 12d, and the HIGH position 12e. Each mode control can be switched.
The wiper switch 12 is set to the OFF position 12a by the user's off operation when it is not raining. When the wiper switch 12 is operated from the OFF position 12a to the MIST position 12b, after the wiper device 2 executes the mist mode control in which the window glass 1 is wiped only once, the wiper switch 12 is automatically operated by the biasing force of the compression spring. Is returned to the OFF position 12a.

When the wiper switch 12 is operated from the OFF position 12a to the AUTO position 12c, the wiper device 2 is set to auto mode control that performs an intermittent wiping operation according to the amount of raindrops. An intermittent time setting section 12f (automatic volume) capable of manually setting the intermittent time of the intermittent wiping operation is provided at the tip end portion of the wiper switch 12. The intermittent time setting unit 12f is configured to be able to set the intermittent time by adjusting the amount of rotation of the wiper switch 12 around the axis.
When the wiper switch 12 is operated from the OFF position 12a to the LOW position 12d, the first relay circuit 10 is turned on and the second relay circuit 11 is turned off at the same time. First continuous wiping mode control for performing the wiping operation is set. When the wiper switch 12 is operated from the OFF position 12a to the HIGH position 12e, since the first relay circuit 10 is turned off and the second relay circuit 11 is turned on at the same time, the wiper device 2 is faster than the first continuous wiping mode control. The second continuous wiping mode control for performing the continuous wiping operation is set.

Next, the rain sensor 3 will be described.
As shown in FIGS. 1 to 6, the rain sensor 3 is detachably mounted at a position facing the raindrop detection region set in front of the room mirror 14 and at the upper end of the outer surface of the window glass 1. Therefore, by electrically connecting the rain sensor 3 and the BCM 4 to the vehicle V having different design specifications such as the inclination angle of the window glass 1 and the vehicle body dimensions, the rain sensor 3 can be arbitrarily attached later. It is.
The rain sensor 3 includes three sets of raindrop detection means 20, a set of imaging means 30, a microcomputer (hereinafter referred to as a microcomputer) 40 (control means), a substantially rectangular parallelepiped housing 3a that can accommodate these, and the like. It has.

As shown in FIG. 4, since the three sets of raindrop detection means 20 have the same configuration, the one set of raindrop detection means 20 will be mainly described.
As shown in FIGS. 5 and 6, the raindrop detection means 20 includes a light projecting unit 22, a light projecting unit control unit 23 that controls the light projecting unit 22, a parallel light lens 24, a condensing lens 25, A light receiving unit 26 (first optical means) and a light receiving unit control unit 27 for controlling the light receiving unit 26 are provided.

The light projecting unit 22 is formed by a light emitting element (for example, an LED), and is configured to be able to irradiate infrared rays α to a portion corresponding to the raindrop detection region on the inner surface of the window glass 1.
The light projecting unit control unit 23 is configured to be able to control the operation timing of the light projecting unit 22, the irradiation amount (intensity) of the infrared ray α, and the like based on a control signal from the microcomputer 40.
As shown in FIG. 6, the parallel light lens 24 has a convex surface on the light projecting portion 22 side and a flat surface on the wind glass 1 side, and the traveling direction of the infrared rays α irradiated from the light projecting portion 22. Is changed from the diffusion direction to the parallel direction. The parallel light lens 24 has an inclination angle or the like so that the infrared ray α is totally reflected from the outer boundary surface of the window glass 1 when no raindrop W is attached to the outer surface of the window glass 1.

The condensing lens 25 is formed such that the surface on the window glass 1 side is convex and the surface on the light receiving unit 26 side is flat. Since both the infrared ray α reflected from the outer boundary surface of the wind glass 1 or the infrared ray α2 reflected from the outer boundary surface of the raindrop W travels in parallel, the condenser lens 25 transmits these parallel infrared rays α or α2. The traveling direction of the infrared rays α or α2 is changed from the parallel direction to the converging direction so as to concentrate on the light receiving unit 26.
The light receiving unit 26 includes a light receiving element (for example, a photodiode), and is configured to detect infrared rays α and α2 reflected from the outer boundary surface of the window glass 1 and the outer boundary surface of the raindrop W. The light receiving unit control unit 27 is configured to be able to control the light receiving sensitivity, focus, and the like of the light receiving unit 26 based on the control signal from the microcomputer 40, and the infrared α or α2 detection signal detected by the light receiving unit 26 to the microcomputer 40. Output.

Here, the raindrop detection principle of the raindrop detection means 20 will be briefly described with reference to FIG.
As shown in FIG. 6, the raindrop W is formed in a flat shape due to the influence of the hydrophilic characteristics of the wind glass 1 and gravity.
The parallel light lens 24 has an inclination angle or the like so that the infrared ray α irradiated from the light projecting unit 22 is totally reflected from the planar outer boundary surface between the window glass 1 and the external space. In a portion where no raindrop W is attached to the outer side surface, the infrared ray α irradiated from the light projecting unit 22 is totally reflected from the outer boundary surface of the window glass 1 without passing through the window glass 1. Further, in the portion where the raindrops W drop and the flat raindrops W adhere to the outer surface of the window glass 1, some of the infrared rays α1 emitted from the light projecting unit 22 are part of the infrared rays α1. The remaining infrared rays α2 (α−α1) are reflected from the outer boundary surface between the raindrops W and the external space. Thereby, the raindrop detection means 20 detects the amount of reflected light of the infrared ray α or α2 that is the reflected light from the outer surface of the window glass 1 or the raindrop W.

As shown in FIG. 4, the imaging means 30 is installed adjacent to the raindrop detection means 20.
As shown in FIG. 5, the imaging unit 30 includes a light projecting unit 32, a light projecting unit control unit 33 that controls the light projecting unit 32, a parallel light lens 34, an imaging lens 35, a light receiving unit 36, A light receiving unit control unit 37 for controlling the light receiving unit 36 is provided.

The light projecting unit 32 is formed of a light emitting element (for example, LED), and is configured to be able to irradiate infrared rays α toward the raindrops W attached to the raindrop detection region on the outer surface of the window glass 1.
The light projecting unit control unit 33 is configured to be able to control the operation timing of the light projecting unit 32 and the irradiation amount (intensity) of the infrared ray α based on a control signal from the microcomputer 40.
The parallel light lens 34 has a convex surface on the light projecting portion 32 side and a flat surface on the wind glass 1 side, and the traveling direction of the infrared ray α emitted from the light projecting portion 32 changes from the diffusion direction to the parallel direction. It has changed.

The imaging lens 35 is disposed so as to focus the imaging information of the raindrop W attached to the outer surface of the window glass 1 corresponding to the raindrop detection area on the light receiving unit 36.
The light receiving unit 36 is configured by an imaging element (for example, a CCD) and configured to be able to image the raindrop W. The light receiving unit control unit 37 is configured to be able to control the light receiving sensitivity and focus of the light receiving unit 36 based on a control signal from the microcomputer 40, and outputs an analog image signal corresponding to the imaging information to the microcomputer 40.

Next, the microcomputer 40 will be described.
The microcomputer 40 detects the amount of raindrops adhering to the outer surface of the window glass 1 based on the reflected light amount of the infrared ray α or α2 detected by the raindrop detection means 20, and creates an image of the raindrop W picked up by the image pickup means 30. Based on this, the raindrop diameter r (diameter) of the raindrop W adhering to the outer surface of the window glass 1 and the deposition speed v of the raindrop W are detected. The microcomputer 40 controls the wiping characteristics of the wiper device 2 according to the raindrop amount, the raindrop diameter r, and the adhesion speed v.
As shown in FIG. 5, the microcomputer 40 includes a raindrop detection processing unit 41, a raindrop amount measurement unit 42 (raindrop amount detection unit), an image processing unit 43, a raindrop diameter measurement unit 44, and an adhesion rate measurement unit 45. The control base includes an auto wiper determination unit 46, a wiper control unit 47, and the like.

In the raindrop detection processing unit 41, an average output is calculated for each reflected light output received by the three sets of light receiving units 26, and a value obtained by converting the average output to a negative value and adjusting the minimum value to zero is obtained. It is set as output x.
As shown in FIG. 7, since the deposition rate of raindrops W on the window glass 1 is proportional to the output x, the raindrop amount measurement unit 42 uses the raindrop detection processing unit 41 based on this correlation. The set output x is converted into an adhesion rate X (%).
Here, the adhesion rate X of the raindrop detection means 20 converted from the output x is set to 0% when there is no raindrop W adhering to the window glass 1, and the raindrop W adheres to the entire surface of the window glass 1. Is set so that the adhesion rate is 100%.
In FIG. 7, the output x is not output below a predetermined raindrop adhesion rate (for example, 1.0%) because of the detection accuracy of the raindrop detection means 20.

  The raindrop amount measuring unit 42 measures the amount of raindrops adhering to the window glass 1 based on the decreasing tendency (decrease width) of the average output of each reflected light received by the three sets of light receiving units 26 of the raindrop detecting means 20. Yes. The raindrop amount measured based on the output value of the raindrop detection means 20 corresponds to the raindrop amount detected by the rain sensor 3. In this embodiment, it is determined that there are raindrops due to rain when the adhesion rate X is 2% or more in consideration of external factors and the like.

The image processing unit 43 converts an analog image signal corresponding to imaging information of the raindrop W attached to the outer surface of the window glass 1 into an 8-bit digital image signal by an A / D converter (not shown). Since the image of one frame imaged by the imaging means 30 is expressed as an aggregate of a plurality of pixels having luminance (brightness), the digital image signal represents each pixel of one frame with an 8-bit gray value ( 0-255).
The digital image signal is subjected to filtering processing in order to enhance the feature amount of the captured image, and then binarized based on a predetermined threshold value related to luminance.

The raindrop diameter measuring unit 44 measures the raindrop diameter r based on the binarized image information.
A horizontal scanning method or a vertical scanning method is applied to the binarized image to extract a plurality of pixels corresponding to the raindrop boundary portion which is a boundary candidate point of the raindrop W, and these pixels and raindrops W of a plurality of sizes are extracted. The raindrop diameter r of the raindrop W detected by matching with the template corresponding to is measured.
The raindrop diameter r may be measured by calculating an approximate curve by connecting a plurality of pixels corresponding to the raindrop boundary portion and determining the raindrop W.

  The adhesion speed measurement unit 45 measures the adhesion speed v based on the output x set by the raindrop detection processing unit 41. The adhesion rate measuring unit 45 calculates the difference between the first output x set earlier and the second output x set after a predetermined time (for example, 1 to 2 sec) from the first output x. The adhesion speed v is calculated by dividing by a predetermined time. It is also possible to calculate the adhesion speed v using the adhesion rate X instead of the output x.

The auto wiper determination unit 46 determines whether or not the user has operated the wiper switch 12 (see FIGS. 2 and 3) to select the auto mode control.
The wiper control unit 47 sets the wiping capability of the wiper device 2 based on the basic function of controlling the wiper device 2 in accordance with the mode control selected by the user and the amount of raindrops detected by the rain sensor 3 in the auto mode control. A capability setting function and a wiping capability adjustment function for adjusting the wiping capability of the wiper device 2 based on the raindrop diameter r and the adhesion speed v of the raindrop W are provided.

The wiping capability setting function of the wiper control unit 47 will be described.
As shown in FIGS. 8 and 9, the wiper control unit 47 includes a wiping speed map M1 and an intermittent time map M2 used when the auto mode control is selected.
As shown in FIG. 8, the wiping speed map M <b> 1 sets a correlation between the raindrop amount detected by the rain sensor 3 and the wiping speed of the wiper device 2. In the wiping speed map M1, there is set a wiping speed characteristic V1 that increases according to the raindrop amount up to the raindrop amount L1 and is constant at the raindrop amount L1 or more. As shown in FIG. 9, the intermittent time map M <b> 2 sets a correlation between the raindrop amount detected by the rain sensor 3 and the intermittent time of the wiper device 2. The intermittent time map M2 is set with an intermittent time characteristic T1 that decreases according to the raindrop amount up to the raindrop amount L1 and becomes zero when the raindrop amount L1 or more. These wiping speed characteristics V1 and intermittent time characteristics T1 are basic wiping characteristics in a raindrop state in which the raindrop diameter r is the reference raindrop diameter A and the deposition speed v is the reference deposition speed B.

Next, the wiping ability adjustment function of the wiper control unit 47 will be described.
The wiper control unit 47 increases the wiping capability of the wiper device 2 when the raindrop diameter r is small compared to when the raindrop diameter r is large, and when the deposition speed v is low, the wiper device 47 compared with when the deposition speed v is high. The wiping speed characteristic V2 and the intermittent time characteristic T2 for increasing the wiping capability 2 are set based on the wiping speed characteristic V1 and the intermittent time characteristic T1.

The wiping speed characteristic V2 after the wiping ability adjustment can be expressed as the following formula (1).
V2 = V1 + K1 + K2 (1)
K1 and K2 are respectively expressed as the following equations, where A is the value of the reference raindrop diameter A, r is the value of the raindrop diameter r, B is the value of the reference deposition speed B, and v is the value of the deposition speed v. Can do.
K1 = k1 × (A−r)
K2 = k2 × (B−v)
K1 and k2 (0 <k1, k2) are predetermined coefficients.
When the raindrop diameter r is smaller than the reference raindrop diameter A and the attachment speed v is lower than the reference attachment speed B, the wiping speed characteristic V2 is set to a wiping ability higher than the wiping speed characteristic V1, as shown in FIG. . When the amount of raindrops is L2 or more, the speed is the same as the wiping speed characteristic V1.

The intermittent time characteristic T2 after adjusting the wiping ability can be expressed as the following equation (2).
T2 = T1-K3-K4 (2)
K3 and K4 are respectively expressed as the following equations, where A is the value of the reference raindrop diameter A, r is the value of the raindrop diameter r, B is the value of the reference deposition speed B, and v is the value of the deposition speed v. Can do.
K3 = k3 × (A−r)
K4 = k4 × (B−v)
Note that k3 and k4 (0 <k3, k4) are predetermined coefficients.
When the raindrop diameter r is smaller than the reference raindrop diameter A and the attachment speed v is lower than the reference attachment speed B, the wiping speed characteristic T2 is set to a wiping ability higher than the wiping speed characteristic T1, as shown in FIG. . In addition, in the raindrop amount L2 or more, the same intermittent time as the wiping speed characteristic T1 is zero.

Next, the wiper control process will be described based on the flowchart of FIG. Si (i = 1, 2,...) Indicates a step for each process.
First, it is determined whether or not the ignition of the automobile V is on (S1). If the ignition is not on, S1 is repeated.
When the ignition is in the on state, the process proceeds to S2, and it is determined whether or not the wiper switch 12 is in the on state other than the off operation. If the wiper switch 12 is not in the ON state, S2 is repeated.

When the wiper switch 12 is in the on state, the process proceeds to S3, and it is determined whether or not the auto mode control is set. When the auto mode control is not set, the process proceeds to S13, the mode control other than the auto mode control set by the user is executed, and the process returns.
When the auto mode control is set, the process proceeds to S4, and it is determined whether or not raindrops are detected. If no raindrop is detected in S4, S4 is repeated.

If raindrops are detected as a result of the determination in S4, the first output x is set (S5), and it is determined whether or not a predetermined time has passed (S6).
If the result of determination in S6 is that the predetermined time has not elapsed, S6 is repeated.
As a result of the determination in S6, if the predetermined time has elapsed, the second output x after the predetermined time has elapsed is set from the first output x set in S5 (S7), and the first output x and the second output The adhesion speed v is calculated based on the output x and the predetermined elapsed time (S8).

Next, after measuring the raindrop diameter r of the raindrop W adhering to the outer surface of the window glass 1 (S9), the process proceeds to S10, where the raindrop diameter r and the deposition speed v coincide with both the basic raindrop diameter A and the basic deposition speed B. It is determined whether or not.
As a result of the determination in S10, when the raindrop diameter r and the attachment speed v both coincide with the basic raindrop diameter A and the basic attachment speed B, the process proceeds to S11, and the wiping speed characteristics V1 and the intermittent time preset in the maps M1 and M2 are transferred. The characteristic T1 is determined as the wiping characteristic of the wiper device 2 (S11), and the process proceeds to S12.

In S12, after performing auto mode control with the wiping speed characteristic and the intermittent time characteristic determined in the preceding step, the process returns.
As a result of the determination in S10, when at least one of the raindrop diameter r and the deposition speed v does not match the basic raindrop diameter A or the basic deposition speed B, the process proceeds to S14.
In S14, the raindrop diameter r and the adhesion speed v are substituted into the equations (1) and (2) to determine the wiping speed characteristic V2 and the intermittent time characteristic T2, respectively, and the process proceeds to S12.

Next, operations and effects of the rain sensor 3 according to the first embodiment will be described.
According to this rain sensor 3, the raindrop diameter r, which is one of the main factors giving visual annoyance to the user, can be detected, so the raindrop diameter r of the raindrop W attached to the wind glass 1 is detected. In addition, when the raindrop diameter r is small, the wiping ability of the wiper device 2 can be made higher than when the raindrop diameter r is large, thereby effectively eliminating the visual annoyance of the user.

  An attachment speed measuring unit 45 for measuring the attachment speed v of the raindrop W attached to the outer surface of the wind glass 1 is provided, and the microcomputer 40 has a wiping ability of the wiper device 2 when the attachment speed v is low compared to when the attachment speed v is high. Is high. This makes it possible to detect the deposition speed v of the raindrop W, which is one of the main factors that cause visual annoyance to the user. Therefore, when the deposition speed v is low, compared to when the deposition speed v is high. The wiping ability of the wiper device 2 can be increased to more effectively eliminate the user's visual troublesomeness.

A light receiving unit 26 for irradiating light on the inner surface of the wind glass 1 and detecting the reflected light reflected by the window glass 1 is provided, and a raindrop amount measuring unit 42 for detecting the amount of raindrops based on the output x of the light receiving unit 26 is provided. Therefore, the amount of raindrops can be accurately detected based on the reflected light reflected by the window glass 1.
Since the wiper device 2 is configured so that at least one of the wiping speed and the intermittent period can be changed, the forward visibility of the user can be kept good regardless of the attribute of the raindrop.

Next, the rain sensor 3A according to the second embodiment will be described with reference to FIGS. The same main components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different components are described.
In Example 1, although the amount of raindrops was measured using the decreasing tendency of the reflected light reflected by the wind glass 1, in Example 2, the increase tendency of the reflected light reflected by the raindrop W adhering to the windglass 1 was shown. Used to measure the amount of raindrops.

As shown in FIGS. 11 to 13, the rain sensor 3A includes three sets of raindrop detection means 20A, one set of imaging means 30, a microcomputer 40A, and a substantially rectangular parallelepiped housing 3a that can accommodate these. I have. Since the three sets of raindrop detection means 20A have the same configuration, the one set of raindrop detection means 20A will be mainly described.
As shown in FIG. 13, the raindrop detection means 20A includes a light projecting unit 22A, a light projecting unit control unit 23A that controls the light projecting unit 22A, a parallel light lens 24A, a condensing lens 25A, and a light receiving unit 26A. (Second optical means) and a light receiving unit control unit 27A for controlling the light receiving unit 26A.

The light projecting unit 22A is formed by a light emitting element (for example, LED), and is configured to be able to irradiate infrared rays β to a portion corresponding to the raindrop detection region on the inner surface of the window glass 1.
The light projecting unit control unit 23A is configured to be able to control the operation timing of the light projecting unit 22A, the irradiation amount (intensity) of infrared rays β, and the like based on a control signal from the microcomputer 40A.
As shown in FIG. 13, the parallel light lens 24 </ b> A has a convex surface on the light projecting portion 22 </ b> A side and a flat surface on the wind glass 1 side, and the traveling direction of the infrared rays β irradiated from the light projecting portion 22 </ b> A. Is changed from the diffusion direction to the parallel direction. When the raindrop W is attached to the outer surface of the wind glass 1, the parallel light lens 24 </ b> A is totally reflected from the outer boundary surface between the raindrop W and the external space, and the window β 1 The inclination angle and the like are set so that infrared rays β pass through the window glass 1 when no raindrop W is attached to the outer surface.

The condensing lens 25A has a convex surface on the window glass 1 side and a flat surface on the light receiving part 26A side. Since all of the infrared rays β reflected from the outer boundary surface of the raindrop W travel in parallel, the condensing lens 25A parallels the traveling direction of the infrared β so that the parallel infrared β is concentrated on the light receiving unit 26A. The direction is changed from the direction to the focusing direction.
The light receiving unit 26 </ b> A is configured by an image sensor (for example, a CCD), and is configured to detect the amount of reflected infrared β reflected from the outer boundary surface of the raindrop W attached to the outer surface of the window glass 1. Based on the control signals from the light receiving unit control unit 27A and the microcomputer 40A, the light receiving sensitivity and focus of the light receiving unit 26A can be controlled, and the reflected light amount detection signal of the infrared β detected by the light receiving unit 26A is output to the microcomputer 40A. doing.

Here, the raindrop detection principle of the raindrop detection means 20A will be briefly described with reference to FIG.
As shown in FIG. 13, the parallel light lens 24 </ b> A has an inclination angle and the like so that the infrared rays β irradiated from the light projecting unit 22 </ b> A are totally reflected from the curved outer boundary surface between the raindrop W and the external space. . Therefore, in the portion where the raindrop W is not attached to the outer surface of the window glass 1, the infrared light β irradiated from the light projecting portion 22A passes through the window glass 1 and therefore no reflected light is generated. Further, in the portion where the raindrop W is dropped and the flat raindrop W is attached to the outer surface of the window glass 1, the infrared ray β transmitted through the window glass 1 is totally reflected from the outer boundary surface between the raindrop W and the external space. Is done. Thereby, the raindrop detection means 20A detects the reflected light amount of the infrared ray β which is the reflected light from the outer surface of the raindrop W.

Next, the microcomputer 40A will be described.
The microcomputer 40A is configured to be able to detect the amount of raindrops adhering to the outer surface of the window glass 1 based on the amount of reflected infrared β detected by the raindrop detection means 20A.
As shown in FIG. 12, the microcomputer 40A includes a raindrop detection processing unit 41A, a raindrop amount measurement unit 42A, an image processing unit 43, a raindrop diameter measurement unit 44, an adhesion speed measurement unit 45, and an auto wiper determination unit 46. The light emitting unit control unit 23 and the light receiving unit control unit 27 are electrically connected.

  In the raindrop detection processing unit 41A, the average output is calculated for the output of each reflected light received by the three sets of light receiving units 26A, and this average output is set as the output y. Since the deposition rate of the raindrops W on the wind glass 1 is proportional to the output y, the raindrop amount measuring unit 42A attaches the output y set by the raindrop detection processing unit 41A based on this correlation. The ratio is converted to Y (%). Here, the adhesion rate Y of the raindrop detecting means 20A converted from the output y is set to 0% when there is no raindrop W adhering to the window glass 1, and the raindrop W adheres to the entire surface of the window glass 1. Is set so that the adhesion rate is 100%.

  The raindrop amount measuring unit 32A measures the amount of raindrops adhering to the window glass 1 on the basis of the increasing tendency (increase width) of the average output of each reflected light received by the three sets of light receiving units 26A of the raindrop detecting means 20A. Yes. The raindrop amount measured based on the output value of the raindrop detection means 20A corresponds to the raindrop amount detected by the rain sensor 3A.

  Accordingly, a light receiving unit 26A that irradiates light on the inner surface of the window glass 1 and detects reflected light reflected by the raindrop W attached to the window glass 1 is provided, and a raindrop that detects the amount of raindrops based on the output of the light receiving unit 26A Since the amount measuring unit 32A is provided in the microcomputer 40A, the amount of raindrops can be accurately detected based on the reflected light reflected by the raindrops W adhering to the window glass 1.

Next, a modification in which the above embodiment is partially changed will be described.
1) In the above-described embodiment, the example in which the raindrop detecting unit measures the amount of raindrops based on the increase or decrease in the amount of reflected light from the window glass or the raindrops has been described. It may be measured. In this case, an image pickup means such as a CCD is used for the light receiving portion of the raindrop detection means, and the raindrop adhesion rate is measured by detecting the raindrop itself by image processing. Therefore, the raindrop detection means and the image pickup means can be used together.

2] In the above-described embodiment, the raindrop diameter and the adhesion speed are described as the raindrop attributes. However, the wiping ability of the wiper device may be controlled at least according to the raindrop diameter, and the adhesion speed may be omitted. It is also possible to combine with other raindrop attributes such as raindrop brightness and raindrop color instead of the adhesion speed.

3) In the above-described embodiment, the example in which the CCD is used for the light receiving unit of the imaging unit has been described. However, another imaging element such as a CMOS may be used.
4) In addition, those skilled in the art can implement the present invention in various forms added with various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. is there.

  The present invention provides a raindrop detection device that controls a wiper device in accordance with the amount of raindrops attached to a window glass. When the raindrop diameter is small, the wiper device has a higher wiping capability than when the raindrop diameter is large. Can be eliminated.

DESCRIPTION OF SYMBOLS 1 Window glass 2 Wiper apparatus 3, 3A Rain sensor 20, 20A Raindrop detection means 26, 26A Light-receiving part 30 Imaging means 40, 40A Microcomputer 42, 42A Raindrop amount measurement part 44 Raindrop diameter measurement part 45 Adhesion speed measurement part 47 Wiper control part

Claims (5)

In the raindrop detection device comprising a control means for detecting the amount of raindrops adhering to the outer surface of the wind glass and controlling the wiper device according to the amount of raindrops,
Providing an imaging means for imaging raindrops adhering to the outer surface of the window glass;
The control means increases the wiping capability of the wiper device when the picked-up raindrop diameter is small compared to when the raindrop diameter is large. Provided with an adhesion rate measuring unit for measuring the adhesion rate of raindrops adhering to the outer surface of the window glass,
The raindrop detection device according to claim 1, wherein when the adhesion speed is low, the control unit increases the wiping capability of the wiper device compared to when the adhesion speed is high. Irradiating light on the inner surface of the window glass and providing first optical means for detecting reflected light reflected by the window glass;
The raindrop detection apparatus according to claim 1, wherein a raindrop amount detection unit that detects a raindrop amount based on an output of the first optical means is provided in the control means. A second optical means for irradiating light on the inner surface of the window glass and detecting reflected light reflected by raindrops attached to the window glass;
The raindrop detection apparatus according to claim 1 or 2, wherein a raindrop amount detection unit that detects a raindrop amount based on an output of the second optical means is provided in the control means.   The raindrop detection device according to any one of claims 1 to 4, wherein the wiper device is configured to be capable of changing at least one of a wiping speed and an intermittent period.