JPS5924278A - Obstackle detecting apparatus for vehicle - Google Patents

Abstract

PURPOSE:To wipe off the contaminant on a light transmitting and receiving part caused by dust, muddy rain or the like to inhibit the falling of capacity, by arranging a light emitting part and a light receiving part inside a vehicle so as to pass laser beam and reflected light on the track of the wiper provided to front glass. CONSTITUTION:A light emitting lens 11 and a light emitting lens 12 are attached to the front surface of an obstacle detecting apparatus and fixed to the upper part of a front panel 2 by a screw 14. Laser beam 4 is emitted in front of a vehicle through the light emitting lens 11 and the reflected light 5 from the forward obstacle is received by the light receiving element of a light receiving circuit through the light emiting lens 12 to be converted to an electric signal. A short-distance cut circuit is provided to cut the reflection signal of front glass. A distance to an obstacle is calculated by an operation circuit and, when said obstacle is within a safe distance, the distance to the obstacle is displayed and an alarm is issued.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an obstacle detection device for a vehicle that detects an obstacle in front of a traveling vehicle using a semiconductor laser (1).

Conventionally, as a device of this type, there is a "Vehicle Obstacle Detection Device" disclosed in Japanese Patent Application Laid-Open No. 56-77774, in which a light transmitting means and a light receiving means are provided on one side and the other side of the fender mirror, and by transmitting and receiving light by these means, the vehicle can be detected. It is designed to detect obstacles in front.

However, since the fender mirror itself is constantly exposed to the outside of the vehicle, its surface becomes dirty due to debris, mud, rain, etc.
Therefore, there is a problem in that the performance for detecting obstacles deteriorates.

The present invention has been made in view of the above-mentioned problems, and by installing at least a light emitting section and a light receiving section at a predetermined position in the vehicle interior where both the laser beam and the reflected light pass on the trajectory of the windshield wiper, the present invention eliminates the problem of sticking. The object of the present invention is to provide a vehicle obstacle detection device capable of detecting obstacles in front of the vehicle without degrading performance by removing dirt on a light transmitting/receiving system due to muddy rain or the like.

The present invention will be described below with reference to embodiments shown in the drawings.

In Fig. 1, (A> is the main cut (2) on the side of the vehicle, and (B) is a view of the interior of the vehicle viewed from the direction of the front panel.■ is the obstacle detection device, and 2 is the front In the panel, 3 indicates a portion of the windshield on the trajectory of the wiper, 4 is a laser beam emitted from an obstacle detection device, and 5 is reflected light when the laser beam 4 hits an object and is reflected.

FIG. 2 is a block diagram showing the system of the obstacle detection device 1. In the figure, numeral 11 is a convex lens for emitting light that narrows the emitted laser light to an appropriate divergence angle, and numeral 12 is a convex lens for light receiving that focuses the reflected light.

20 is a trigger circuit that generates a trigger pulse for causing a laser diode (not shown) to emit light; 30 is a light emitting circuit that drives the laser diode to emit laser light in synchronization with the trigger pulse signal; 40 is a light emitting circuit that is focused by the light receiving lens 12; A light-receiving circuit receives the reflected light with a light-receiving element (for example, a photodiode, not shown), converts the light into an electrical signal, and amplifies it; 50 is a signal processing circuit that receives the output of the light-receiving circuit as an input and calculates the timing of the reflected light; A short-range (3) cut circuit 70 to prevent false detection due to laser light reflected by the windshield uses the signals of the trigger circuit 20 and the short-range cut circuit 60 as input, counts the time from emission to light reception, and calculates the distance in front. An arithmetic circuit which calculates the distance to an obstacle and uses a signal S from a speedometer (not shown) as an input to calculate a safe distance for the current traveling speed; 80 is an arithmetic circuit that uses the output of the arithmetic circuit 70 as an input to determine the distance to an obstacle when an obstacle is detected; This is a display/warning circuit that displays the distance to an obstacle on a distance display section (not shown) and issues an alarm when the distance to the obstacle becomes smaller than the safe distance. Moreover, 90 is a power supply circuit for supplying the power necessary to drive the circuit elements of each part by inputting the battery of the vehicle (not shown). Note that the light emitting lens 11 and the light emitting circuit 30 constitute a light emitting section, and the light emitting lens 12 and the light receiving circuit 40 constitute a light receiving section.

FIG. 3 is a diagram showing the installation of the obstacle detection device 1,
FIG. 2 is a view seen from the front of the vehicle through the windshield. A light emitting lens 11 and a light receiving lens 12 are attached to the front surface of the obstacle detection device 1, and a distance display section (4) for displaying the distance to the obstacle is attached to the rear surface. Furthermore, fixing stays 13 are attached to both sides by welding or the like. This obstacle detection device 1 is fixed to a fixing stay 13 and the upper part of the front panel 2 with screws 14.

The operation of the above configuration will be explained with reference to the time chart of FIG. 4. Now, in the trigger circuit 20, as shown in FIG.
Trigger pulses as shown in are periodically generated. At the rising edge of the trigger pulse, a laser diode (not shown) of the light emitting circuit 30 is driven to emit laser light as shown in FIG. This laser light is emitted toward the front of the vehicle through the light emitting lens 11. The reflected light hitting the obstacle in front is received by a not-shown light-receiving element of the light-receiving circuit 40 via the light-receiving lens 12. The light receiving circuit 40 then converts the received reflected light into an electrical signal. The waveform of the electric signal at this time is, for example, as shown in FIG. 4(C). here,
P 1 is the reflected light reflected by the windshield, and P
2 shows the reflected light reflected by an obstacle in front. The peak value of this received light signal is detected by the signal processing circuit 50 (5), and as shown in FIG.
Signals TI and T2 corresponding to +P2 are output. The output signal of this signal processing circuit 50 is input to a short distance cut circuit 60 together with the output signal of the trigger circuit 20, and is sent at a short distance (for example, 1 to 2 meters from the light emitting part to the front of the vehicle) to prevent malfunction.
Time corresponding to τ2 (short distance!, speed of light C, then τ2=
24/c) is cut and the subsequent signals are used as reflected signals.

In Fig. 4(e), the time from the rise of the trigger pulse shown in Fig. 4 (al) to the peak value of light emission is always delayed by a constant value τl. During this period, a high level signal (shown in Figure 4(e)) is generated.When this signal is at a high level, the signal in Figure 4 (dl) is cut.
Cut the reflected signal T1 from the windshield. and,
A signal shown in FIG. 4 (fl) that rises at the rising edge of the trigger pulse (FIG. 14 (al) and falls at the reflected signal T2) is output from the signal processing circuit 60 and input to the arithmetic circuit 70. During the high level of the signal in f), the time is determined by counting with a color (6) counter (not shown), and the time τ1 is subtracted from it to obtain the time t from the peak of light emission to the peak of light reception shown in Figure 4 (f+). The distance to the obstacle is determined by calculating c''-t/'l, and a signal indicating this distance is output.Meanwhile, a signal S from a speedometer (not shown) is input to the calculation circuit 70, and the distance to the obstacle is determined. Detects the speed of the vehicle and calculates the safe distance to the obstacle in front for a predetermined running speed.If the distance to the previous obstacle is greater than or equal to the safe distance, the level is set to low, and if it is within the safe distance, the level is set to high. The output signal of the arithmetic circuit 70 is sent to the display alarm circuit 8.
It is input to 0 and displays the distance to the obstacle,
A warning is issued when the distance to an obstacle is within a safe distance.

FIG. 5 shows another embodiment. In FIG. 5, the obstacle detection device 1 is fixed to the back side of the rearview mirror 3, and is positioned in relation to the windshield so that it can see through the trajectory of the wiper.

In FIG. 5, the entire device is fixed to the back side of the rearview mirror 3, but the light emitting circuit 30. It is also possible to separate the light receiving circuit 40 and (7) and other parts, and fix only the former to the back side of the rearview mirror 3, and incorporate the other parts elsewhere, for example, on the front panel, to reduce the weight of the rearview mirror 3. .

Further, the distance display section in the display/warning circuit 80 may be separated and incorporated into the instrument panel.

As described above, in the present invention, in a device that uses a semiconductor laser to detect an obstacle in front of a traveling vehicle, at least the light emitting part and the light receiving part are arranged so that both the laser light and the reflected light are on the trajectory of the windshield wiper. Since the sensor is installed at a predetermined position in the vehicle interior where the windshield passes through, even if the windshield becomes dirty, the wiper operates to wipe off the dirt, so there is almost no dirt on the front surface of the light emitting section and the light receiving section, and therefore the detection ability is improved. This has the excellent effect of being able to stably detect obstacles in front of the vehicle without causing a decrease in performance.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram showing how the obstacle detection device is installed on the vehicle (8), Figure 2 is a block diagram showing the configuration of the obstacle detection device, and Figure 3 is the front panel of the obstacle detection device. FIG. 4 is a time chart for explaining the operation, and FIG. 5 is a schematic configuration diagram showing another embodiment. 1... Obstacle detection device, 2... Front panel, 3
...Rearview mirror, 11...Light-emitting lens, 12...
- Light receiving lens, 30... Light emitting circuit, 4o... Light receiving circuit. Representative Patent Attorney Takashi Okabe (9) @Figure 1 (A') (B) @Figure 3 Figure 4

Claims (1)

[Scope of Claims] (11) A device for detecting an obstacle in front of a traveling vehicle using a semiconductor laser, comprising a light emitting section that emits a laser beam and a light receiving section that receives reflected light; An obstacle detection device for a vehicle, characterized in that a part and a light receiving part are installed at a predetermined position in a vehicle interior where both the laser beam and the reflected light pass on the trajectory of a windshield wiper. (2) The predetermined position is (3) The vehicle obstacle detection device according to claim 1, wherein the predetermined position is on the front panel. The vehicle obstacle detection device according to item 1.