JPH02124418A - Optical distance measuring equipment to be mounted on vehicle - Google Patents

Abstract

PURPOSE:To obtain continuous measured values by a method wherein two same distance measuring modules are placed side by side, and outputs of the distance measuring modules are processed by an OR circuit with a protection glass surface in front of the modules wiped off with a wiper. CONSTITUTION:When rain drops or the like attach on a protection plate 2, a sensor detects them, and a wiper 4 makes reciprocating action to wipe off the rain drops or the like on the plate 2 surface. At this time, the wiper 4 momentarily goes across a visual field of distance measuring modules 1a, 1b. Since two same modules 1a, 1b are placed side by side and the width of the wiper 4 is narrow, even if the visual field of one module is interfered, output can be obtained from the other module. As a result, by processing outputs of the two modules 1a, 1b with an OR circuit incorporated in a controller 7, continuous measured values can be obtained even during wiper operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical distance measuring device mounted on an automobile.

[Conventional technology]

BACKGROUND ART Conventionally, attempts have been made to install a distance 1Ii11'/s determining device on a vehicle for purposes such as automatic driving and collision prevention. There are radar, ultrasonic, and optical methods for this device, but due to the remarkable progress of autofocus cameras in recent years, the optical method is the most suitable in terms of cost, as it has become possible to utilize the range-finding module. ing. However, optical systems have a fatal drawback when used in automobiles, as distance measurement becomes impossible if the lens surface becomes dirty with raindrops or dust.

[Problem to be solved by the invention]

In order to avoid the above-mentioned problems, devices have been mounted inside the vehicle, but in this case there are problems such as being able to measure long distances but not being able to detect objects that are directly near the vehicle. Another method is to use a wiper to wipe off raindrops and dirt, but the measured values are intermittent while the wiper is wiping, which is a problem when used in automobiles, which primarily measure moving objects.

This invention was made in order to solve the above-mentioned problems, and it is possible to detect objects in the immediate vicinity of the car by mounting a measuring device on the outside of the car, and also to avoid intermittent measurement values. The purpose is to obtain a vehicle-mounted optical distance measuring device.

[Means to solve the problem]

The vehicle tower-mounted optical distance measuring device according to the present invention includes two distance measuring modules arranged in parallel in the same direction, each consisting of a convex lens and a semiconductor distance measuring element, and a protective plate consisting of a transparent plate placed in front of these distance measuring modules. The device is equipped with a raindrop sensor for detecting dirt on the plate surface, a wiper for wiping dirt from the protective plate surface, and an OR circuit for processing and extracting the signal output from the distance measuring module.

[For production]

In this invention, when raindrops or dust adhere to the transparent surface in front of the ranging module, a sensor detects this and automatically operates a wiper to wipe away the raindrops and dust.

Moreover, since the outputs of the two distance measuring modules are taken out by an OR circuit, continuous measured values can be obtained even when the wiper is in operation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a front view of the vehicle tower-mounted optical distance measuring device according to the present invention, and FIG. 2 is a sectional view taken along line nn in FIG. Two identical one-length mosieres arranged side by side as constituent members,
This is similar to the infrared active ranging module used in lens-shutter autofocus cameras or the ranging module used in single-lens shutter autofocus cameras. Reference numeral 2 denotes a protective plate made of a transparent glass plate placed in front of the distance measuring module 1, and is attached to the cylinder body 3. Note that the space between the ranging modules la, lb and the protective plate 2 has an airtight structure to prevent dust and rainwater from entering from the outside. A wiper 4 wipes the front surface of the protection plate 2 in the direction of an arrow in FIG. 1, and is operated by a drive device 5. 6 is a raindrop sensor that detects raindrops and dust attached to the protective glass 2, details of which are shown in Figure 3.
In the figure, 61 is a light source such as a light emitting diode, 62 and 63 are condensing lenses, 64 is a light receiving element such as a photodiode,
Reference numeral 65 indicates raindrops attached to the protective glass 2 surface. To explain the operating principle of this raindrop sensor 6, when the surface of the protective plate 2 is clean, most of the light from the light source 61 passes through, When rain 'a65 adheres to the front surface of the plate, the light ai6t is scattered at this part and the light receiving element 6
4. In addition to raindrops, dirt caused by dust can also be detected in the same manner as described above. Further, the raindrop sensor 6 is connected to the wiper 4 via a controller 7, as shown in the block diagram of FIG. In FIG. 2, numeral 8 is a hood that prevents raindrops and dust from adhering to the protective glass 2, and also has the function of canting excess oblique light.

Next, the operation according to the present invention will be explained. When there are no raindrops etc. attached to the cover plate 2, the output of the raindrop sensor 6 is zero, so the wiper 4 does not operate. Therefore, the wiper remains stationary outside the field of view of the ranging modules la and lb, and the module outputs the same distance measurement value. In this way, when F:g droplets etc. adhere to the protective plate 2, the sensor 6 detects this, and the soiper 4 moves back and forth to remove the protective glass 2.
Wipe and remove dirt from the surface. At this time, the wiper 4 temporarily blocks the field of view of the distance measurement modules la and lb, but in this invention, two identical distance measurement modules are arranged side by side, and the width of the wiper 4 is narrow. Even if the field of view of the distance measurement module is blocked, output can be obtained from the other distance measurement module. As a result, by processing the outputs of the two distance measuring modules la and lb using the OR circuit built into the controller 7, continuous measured values can be obtained even during wiper operation.

FIG. 5 shows another embodiment of the wiper, in which the wiper 4 is moved back and forth, whereas the wiper 4d is rotated in the direction of the arrow to wipe two surfaces of the protective glass. In this case as well, when the wiper is not operating, it is stopped at a position where it does not block the field of view of the ranging modules la and lb, and even though the field of view of one ranging module is blocked by the wiper 43, it cannot be seen from the other ranging module. The output obtained is the same as in the above embodiment.

In the embodiment, a case has been described in which the outputs of the two distance measurement modules are processed by the OR circuit, but the outputs of the two distance measurement modules may be switched in synchronization with the movement of the wiper.

〔Effect of the invention〕

As explained above, according to the present invention, two identical distance measuring modules are arranged side by side, the protective glass surface in front of the module is wiped with a wiper, and the output of the distance measuring module is processed by an OR circuit. Therefore, even during wiper operation, continuous measurement values can be obtained without intermittent measurement values, resulting in a vehicle-mounted optical distance measurement device with high reliability.

[Brief explanation of drawings]

FIG. 1 shows a vehicle-mounted optical path M according to an embodiment of the present invention.
A front view of the IS fixing device, Figure 2 is a sectional view taken along the ■n line in Figure 1,
FIG. 3 is a principle diagram of the raindrop sensor, FIG. 4 is a block diagram of the device of the invention, and FIG. 5 is a front view of another embodiment of the wiper. la, lb... Distance measurement module, 2... Protective glass, 4.43... Wiper 6... Raindrop sensor, controller Φ Note that the same reference numerals in the drawings indicate the same or equivalent parts. No.! Figure 2

Claims (1)

[Claims] Two distance measuring modules made of a convex lens and a semiconductor distance measuring element arranged side by side in the same direction, a protective plate made of a transparent plate placed in front of these distance measuring modules, and a raindrop sensor for detecting dirt on the surface of the plate. A vehicle-mounted optical distance measuring device comprising a wiper for wiping dirt off the surface of a protective plate, and an OR circuit for processing and extracting the signal output from the distance measuring module.