JPH06242241A - Distance measuring apparatus - Google Patents

Abstract

PURPOSE:To obtain a low-cost distance measuring apparatus by obtaining a wide measuring range by one illumination light source. CONSTITUTION:A distance measuring apparatus irradiates an object with a laser light from a light emitting element 4A, receives its reflected light by a light receiving element 8, measuring this propagating delay time by a signal processor 10A, rotates a light transmitting lens 5A for condensing the laser light from the element 4A by a motor 12 at its light irradiating direction as an axis, and varies its irradiating direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates laser light as light, detects reflected laser light from an object, and measures the propagation delay time from the light emission to the light reception to measure the distance to the object. The present invention relates to a distance measuring device for obtaining.

[0002]

2. Description of the Related Art As this type of distance measuring device, there is known an optical distance measuring device using a laser beam as disclosed in, for example, Japanese Patent Laid-Open No. 61-259185. FIG. 5 is a block diagram showing the configuration thereof. This distance measuring device includes a light transmitting device 1 that emits a laser beam and a laser beam emitted from the light transmitting device 1 for an object such as a preceding vehicle or an obstacle. The light receiving device 2 which receives the reflected light reflected upon hitting the light source 14, and the light transmitting device 1 and the light receiving device 2 are connected to output a light emission signal to the light transmitting device 1 and to receive the reflection signal from the light receiving device 2. And a signal processing device 10 that is used.

The light transmitting device 1 includes three light emitting elements 4a, 4b and 4c composed of laser diodes, and a pulse wave driving device 3 connected to the light emitting elements 4a, 4b and 4c.
And a light transmitting lens 5 arranged in front of the light emitting elements 4a, 4b and 4c, and the light emitting element 4 is driven by the pulse wave driving device 3.
The laser light is emitted by driving a, 4b, and 4c. The light emitted by each of the three light emitting elements 4a, 4b, 4c passes through the light transmitting lens 5 and is condensed with a predetermined spread angle.

The light receiving device 2 has a light receiving lens 7 arranged on the front surface thereof, a light receiving element 8 arranged at a focal position behind the light receiving lens 7, and an amplifying device 9 connected to the light receiving element 8. However, the amplification device 9 is connected to the signal processing device 10. Then, when the laser beams 15a, 15b, 15c collected by the light transmitting lens 5 of the light transmitting device 1 are reflected by the object 14 such as a preceding vehicle and pass through the light receiving lens 7,
The light is collected by the light receiving element 8 and converted into an electric signal. This electric signal is amplified as a reflected signal by the amplifying device 9 and then input to the signal processing device 10, and the signal processing device 10 measures the delay time from light transmission to light reception to detect a preceding vehicle or an obstacle. Distance is required.

[0005]

As described above, the conventional distance measuring device is provided with a plurality of light emitting elements 4a, 4b, 4c,
The irradiation range of the laser beam is expanded by sequentially changing the irradiation direction of the laser beam, and the preceding vehicle and obstacles are detected over the expanded range. However, in such a technique, a plurality of optical systems for converging the irradiation light to a predetermined beam angle are required, and the size of the entire apparatus increases and the cost becomes high. When condensing light, a plurality of light emitting elements are required, and using a plurality of expensive light emitting elements causes a problem that the entire device becomes expensive.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to eliminate the need for providing a plurality of irradiation light sources.
An object of the present invention is to obtain a distance measuring device capable of switching the irradiation direction of laser light with one optical system and an irradiation light source.

[0007]

According to a first aspect of the present invention, there is provided a distance measuring device which emits light toward an object and light emitting means which emits the light in a predetermined spread and direction. Irradiation of the light by condensing the lens, light receiving means for receiving the reflected light of the condensed light by the object, and rotating the lens around the light emitting direction in synchronization with the light emitting timing of the light emitting means. A lens rotation device that changes the direction and a processing device that determines the distance to the object by measuring the propagation delay time from the emission of the light to the reception of the reflected light are provided.

According to a second aspect of the present invention, there is provided a distance measuring device which emits light toward an object and a lens which collects the light emitted by the light emitting device in a predetermined spread and direction. And a light receiving means for receiving the reflected light of the condensed light by the object, and the light emitting direction is changed by rotating the lens around the light emitting direction in synchronization with the light emitting timing of the light emitting means. Irradiation is performed by obtaining the distance to the object by measuring the propagation delay time from the lens rotation device and the light emission to the reception of the reflected light, and detecting the rotation position of the lens rotation device. And a processing device that specifies the direction and limits the measurement range.

[0009]

According to the distance measuring device of the first aspect of the present invention, the light from the light emitting means which is one irradiation light source is condensed through the lens. By rotating around the light emitting direction of the lens light as an axis, the direction in which the object is irradiated can be switched, which enables a wide range of measurement with one optical system and light source.

According to the distance measuring device of the second aspect of the present invention, the light from the light emitting means which is one irradiation light source is condensed through the lens. By rotating around the light emitting direction of the lens light as an axis, the direction in which the object is irradiated can be switched, which enables a wide range of measurement with one optical system and light source. Further, the irradiation range can be limited by specifying the direction in that case.

[0011]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a distance measuring device showing an embodiment of the present invention. The distance measuring device shown in the figure is mounted on a vehicle, for example, and is used for detecting a preceding vehicle or an obstacle existing in the traveling direction of the vehicle and measuring a distance to the preceding vehicle or the obstacle. Is. In the distance measuring device shown in the figure, a light transmitting device 1A for transmitting light and laser light emitted from the light transmitting device 1A hits an object (not shown) such as a preceding vehicle or an obstacle and is reflected. Light receiving device 2A for receiving reflected light, light transmitting device 1A, and light receiving device 2
The distance obtained from the signal processing device 10A and the signal processing device 10A, which is connected to A and outputs a timing signal for emitting laser light to the light transmitting device 1A, and to which the reflected signal from the light receiving device 2A is input, Display device 13 for displaying
Composed of and.

The light transmitting device 1A includes a pulse wave driving device 3 connected to the signal processing device 10A, and the pulse wave driving device 3
And a light emitting element 4A which is a light emitting means for emitting a laser beam in response to a signal from the pulse wave driving device 3 and a laser beam emitted by the light emitting element 4A which is arranged in front of the light emitting element 4A. And a lens rotating unit 6 configured to rotate the light transmitting lens 5A around the light emitting direction of the laser beam as an axis, and the lens rotating unit 6 Attached to the motor 12 for rotating the lens rotating portion 6, and the motor 12
And a motor drive device 11 capable of detecting a rotation angle by a rotary encoder (not shown) or the like.

The light receiving device 2A is provided with a light receiving lens 7 which collects the laser light reflected by the object and a light receiving element which is provided behind the light receiving lens 7 and which receives the collected reflected light. 8 and an amplifying device 9 which is connected to the light receiving element 8 and amplifies the light receiving signal detected by the light receiving element 8.

The signal processing device 10A measures the propagation delay time from the output of the light emission signal to the pulse wave drive device 3 to the output of the light reception signal from the amplification device 9 to obtain the distance to the object and the light emission. The timing is synchronized with the rotation angle of the motor 12. The distance obtained by the signal processing device 10A is displayed on the display device 13.

FIG. 2 is a sectional view showing the details of the lens rotating portion 6. The lens rotating part 6 includes a cylindrical part 6a and a light transmitting lens 5A.
The light-transmitting lens 5A is rotated by 180 degrees about the axis of the cylindrical portion 6a to which the light-transmitting lens 5A is attached in the state shown in FIG. 2A. The state shown in FIG. 2B is obtained. This rotation is performed by the rotation of the motor 12 according to the drive signal from the motor drive device 11, and the signal processing device 10A reads the rotation angle of the lens rotation unit 6 from the signal from the motor drive device 11.
The signal processing device 10A may detect when the light transmitting lens 5A is in the state (a) or the state (b), as shown in FIG. The signal processing device 10A performs processing so as to emit laser light when the light-transmitting lens 5A is in the states of (a) and (b) of FIG. 2 based on the rotation angle of the lens rotation unit 6. , A pulse wave drive device 3 for timing signals for emitting laser light
Output to.

As shown in FIG. 3, the light transmitting lens 5A is set so as to have a predetermined spread angle θ when the laser light is emitted in the state of FIG. 2 (a). For example, the spread angle θ is set to be 5 °. The directivity angle φ at this time is set to 1.5 °.
When set in this way, laser light is emitted as shown in FIG. Next, when the light-transmitting lens 5A is rotated to be in the state of FIG. 2B, laser light is emitted, and irradiation is performed as shown in FIG. 3B. At this time, since the light transmitting lens 5A rotates 180 degrees, the directivity angle φ is -1.5.
It becomes ゜.

As described above, the signal processing device 10A detects from the motor drive device 11 that the light-transmitting lens 5A is in the state of FIG. 2A or 2B, and when this detection is performed, a pulse is output. A pulse wave is generated in the wave driving device 3 and laser light is emitted from the light emitting element 4A. The irradiated laser light passes through the light transmitting lens 5A and is condensed as shown in FIG. At this time, if an object such as a preceding vehicle or an obstacle exists within the irradiation range of the laser light, the light receiving lens 7 collects the reflected light from the object hit by the laser light, and the light receiving element 8 receives the reflected light. The signal is converted into a signal and this electric signal is amplified by the amplifier 9. The amplification device 9 outputs the amplified electric signal to the signal processing device 10A, and outputs a signal for notifying the signal processing device 10A that the irradiated laser beam is received. Upon receiving this signal, the signal processing device 10A measures the delay time from the light emission timing to the light reception timing, calculates the distance to the object, outputs the data to the display device 13, and displays the distance. Thus, by rotating the light transmitting lens 5A, a wide irradiation range can be obtained at low cost without providing a plurality of light emitting elements.

Example 2. In the first embodiment, the light-transmitting lens 5A emits a laser beam without distinguishing between the states of (a) and (b) of FIG. 2 and measures the received propagation delay time, which is displayed as a distance. , (A) and (b) in FIG. 2 of the light transmitting lens 5A can be distinguished from each other and input to the signal processing device 10A, three objects can be obtained as shown in FIG. Things 16a, 16
It can be distinguished that b and 16c are present at different positions as shown in the figure. This will be explained below.

In FIG. 4, when the light transmitting lens 5A is in the state shown in FIG. 2A, the irradiation range of the laser light is the solid line 17a, and the laser light hits the objects 16a and 16c. The reflected light can be detected. Further, when the light transmitting lens 5A is in the state of FIG. 2 (b),
The irradiation range is the wavy line 17b, and the object 16b and the object 16c can be detected. Therefore, the object that can be detected by the light transmitting lens 5A in the state of both lenses is the object 16
c is the only detectable area, and solid line 17a and wavy line 1
It is 17c where 7b overlaps.

By dividing the detectable area in this way, it is possible to limit the distance range to be displayed. For example, when the measured distance is up to 40 m, the display device 13 uses the entire laser light irradiation range of 17a and 17b as the measurement range.
The distance is output to and displayed. When the measured distance is 40 m or more, only the distances detected in both the ranges 17a and 17 are output as the display distance to the display device 13, and when only one of them is detected, the output is not performed. The distance can be limited to be displayed when the object is only in the front lane width, for example. In the above configuration, the lens rotation unit 6 and the motor driving device 1
1 and the motor 12 constitute the lens rotating device in the claims.

[0021]

As described above in detail, according to the distance measuring device of the first aspect of the present invention, the light emitting means for emitting the light toward the object and the light emitted by the light emitting means are predetermined. A lens for converging light in the direction and direction of the light, a light receiving means for receiving the reflected light of the condensed light by the object, and a lens for rotating the lens around the light emitting direction in synchronization with the light emitting timing of the light emitting means. A lens rotation device that changes the irradiation direction of the light, and a processing device that determines the distance to the object by measuring the propagation delay time from the emission of the light to the reception of the reflected light As compared with the conventional distance measuring device having a plurality of irradiation light sources, there is an effect that it can be constructed at a lower cost.

According to the distance measuring device of the second aspect of the present invention, the light emitting means for emitting light toward the object and the light emitted by the light emitting means are condensed in a predetermined spread and direction. The lens, the light receiving means for receiving the reflected light of the condensed light by the object, and the lens rotating about the light emitting direction in synchronization with the light emitting timing of the light emitting means to change the light emitting direction. A lens rotating device to be changed and a distance to an object are obtained by measuring a propagation delay time from the emission of the light to the reception of the reflected light, and the rotational position of the lens rotating device is detected. Since it is equipped with a processing device that specifies the irradiation direction and limits the measurement range, it can be constructed at a lower cost than conventional distance measuring instruments that have multiple irradiation light sources, and the laser beam can be swept by rotating the lens system. An effect that it is possible to ensure an effective irradiation range can be.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a first embodiment of the present invention.

FIG. 2 is a sectional view showing a lens state of Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram showing a light emitting state depending on a state of a lens.

FIG. 4 is a diagram showing an irradiation range.

FIG. 5 is a block configuration diagram showing a configuration of a conventional distance measuring device.

[Explanation of symbols]

 1A Light-sending device 2A Light-receiving device 4A Light-emitting element 5A Light-sending lens 6 Lens rotating part 10A Signal processing device 11 Motor drive device 12 Motor

Claims (2)

[Claims] 1. A light emitting means for emitting light toward an object, a lens for condensing the light emitted by the light emitting means in a predetermined spread and direction, and reflection of the condensed light by the object. A light receiving means for receiving the light; a lens rotation device for rotating the lens around the light emitting direction in synchronization with the light emitting timing of the light emitting means to change the irradiation direction of the light; A distance measuring device comprising: a processing device that obtains a distance to an object by measuring a propagation delay time until the reflected light is received. 2. A light emitting means for emitting light toward an object, a lens for condensing the light emitted by the light emitting means in a predetermined spread and direction, and reflection of the condensed light by the object. A light receiving means for receiving the light; a lens rotation device for rotating the lens around the light emitting direction in synchronization with the light emitting timing of the light emitting means to change the irradiation direction of the light; A processing device that determines the distance to the object by measuring the propagation delay time until receiving the reflected light, specifies the irradiation direction by detecting the rotation position of the lens rotation device, and limits the measurement range. A distance measuring device comprising: