JPS61259185A - Optical range finder - Google Patents

Abstract

PURPOSE:To make it possible to perform a wide range of measurement by a small-sized apparatus, by providing a plurality of light emitting sources and condensing the emitted lights from the light emitting source toward a predetermined direction by one common lens system. CONSTITUTION:A plurality of beam emitting elements 7, 9, 11 are provided in a beam transmitter 1 and one common condensing lens 15 is provided in front of a beam emitting side to condense laser beams 17, 19, 21 emitted from the beam emitting elements 7, 9, 11 to emit the same. The reflected beam from an object 23 to be measured is received by a light receiver 3 and the distance up to the object 23 to be measured is measured on the basis of the propagation delay time from the emission of beam to the reception thereof by a range find ing circuit 5. By this method, measurement in a wide range can be performed and the whole of the apparatus can be miniaturized because the condensing lens system is used commonly by each device.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention measures the distance to the reflector from the propagation delay time from the emission of the light to the reflected light by receiving the reflected light of the emitted light by the reflector. The present invention relates to an optical distance measuring device.

[Prior art and problems of the invention]

For example, in a vehicle, a light beam is emitted in the direction of travel of the vehicle in order to measure the distance to the preceding vehicle or to detect obstacles in front. Detects the preceding vehicle or obstacle by slowing down the light that is reflected by the object, etc., and detects the preceding vehicle or obstacle based on the light propagation delay time from the emission of the eye light to the reception of the reflected light. Various devices have been developed to measure the distance between. Such devices are disclosed, for example, in Japanese Patent Laid-Open No. 59-24278 and Japanese Patent Laid-Open No. 59-34179.

By the way, in such an optical distance measuring device, the radiation range of the light beam can be expanded to detect preceding vehicles or obstacles over a wide range, or the radiation direction of the light beam can be sequentially changed to detect objects within a predetermined range. It is conceivable to provide a plurality of light radiation sources in order to sequentially scan the light. Provide multiple. In other words, if one condensing lens is provided for one light radiation source, multiple lenses will be required and the number of lenses will increase.
There is a problem in that as the price of the device increases, the structure of the device itself also increases, making it difficult to achieve economicalization and miniaturization.

[Purpose of the invention]

This invention was made in view of the above, and its purpose is to make the lenses more economical by making them common.
An object of the present invention is to provide an optical distance measuring device that has achieved miniaturization.

[Summary of the invention]

In order to achieve the above purpose, an optical system that emits light, receives the reflected light from an eye light reflector, and measures the distance to the reflector based on the propagation delay time from the light emission to the reflection and reception of the reflected light. In the distance measuring device, the present invention includes a plurality of light radiation sources that emit the light, and one lens system that focuses the light emitted from the plurality of light radiation sources in a predetermined direction. The gist is that.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram of an optical distance measuring device showing an embodiment of the present invention. The optical distance measuring device shown in the figure is mounted on a vehicle, for example, and is used to detect a preceding vehicle or an obstacle that is present in the direction of travel of the vehicle, and to measure the distance to the preceding vehicle or obstacle. It is something that

The optical distance measuring device shown in the figure includes a light transmitter 1 that emits a light beam, and the light beam emitted from the light transmitter 1 hits a reflector such as a preceding vehicle or an obstacle and is reflected. A light receiver 3 that receives reflected light; and a distance measuring circuit 5 that is connected to the light transmitter 1 and the light receiver 3, and is supplied with a radiation signal from the light transmitter 1 and a reflected signal from the light receiver 3. It consists of

The light transmitter 1 has a plurality of light emitting elements 7, 9.11 made of laser diodes, etc., and the light emitting elements 7, 9.11 are driven by a drive circuit 13 to emit light such as laser light. The light from each light emitting element 7, 9.11 is focused through one common condensing lens 15 into a respective light beam 17.19.
21 and is reflected by hitting an obstacle 23, for example. In addition, the light transmitter 1 drives the light emitting elements 7.9.11 with such a drive circuit 13 to emit a light beam, and at the same time, the light transmitter 1 uses the above-mentioned emitted light to notify the distance measuring circuit 5 of the time point at which the light beam is emitted. The signal is supplied to the ranging circuit 5.

The light receiver 3 receives the reflected light from the light beam emitted from the light transmitter 1 by hitting the obstacle 23 and passing it through the light receiving lens 25 to a light receiving element made of, for example, a phototransistor or a photodiode. The light is received at 27. The reflected light received by the light receiving element 27 is converted into an electrical signal, amplified by the amplifier circuit 29, and then supplied to the distance measuring circuit 5 as a reflected signal.

The distance measuring circuit 5 measures the distance to the obstacle 23 based on the light propagation delay time between the radiation signal supplied from the light transmitter 1 and the reflected signal supplied from the light receiver 3.

In the configuration as described above, the light emitted from the light emitting element 9 disposed at the center is condensed by the condenser lens 15 and radiated as a central beam 19 in the front direction of the condenser lens 15. The spread angle of the light beam 19 in this case can be set to an arbitrary spread angle by adjusting the distance between the light emitting element 9 and the condensing lens 15. Further, the light emitted from the light emitting cables 7 and 11 disposed on both sides of the light emitting element 9 is condensed by a condenser lens 15 and formed into light beams 17 and 21 at the center of the central light beam 19. In other words, the light is emitted at an angle Δθ shifted from the optical axis of the condenser lens 15. This angle Δθ is Δθ=D/L (radians), where L1 is the distance between the light emitting element 9 and the condensing lens 15, and D is the distance between the light emitting element 9 and the light emitting element 7 or 11. Note that the spread angle of the light beam 17.21 can also be arbitrarily adjusted by adjusting the distance between each light emitting element 7, 11 and the condenser lens 15.

In this way, the light from the three light emitting elements 7, 9, 11 is condensed through one condenser lens 15 to form three light beams 17.
, 19.21, it is possible to expand the radiation angle of the light beam, or the radiation range of the straw light beam, and it is possible to detect and measure reflectors such as preceding vehicles and obstacles that exist over a wide range. Furthermore, by emitting each light beam in a sequential scanning manner, it is also possible to accurately detect the angular position where the reflector is present.

More specifically, the drive circuit 13 drives the three light emitting elements 7.
．． When driving 9.11 at the same time, three light beams 17, 19, and 21 are simultaneously emitted from the light emitting element 7°9.11 over a wide range in each direction via the condensing lens 15, and within this wide range, The reflected light from the reflector present in the receiver 3
The light is received by the light receiving element 27 through the light receiving lens 25, and is supplied to the ranging circuit 5 as a reflected signal via the amplifier circuit 29. The distance measuring circuit 5 can measure the distance to the reflector from the radiation signal supplied from the light transmitter 1 and the reflected signal supplied from the light receiver 3.

Further, when driving the light emitting elements 7, 9.11 sequentially from the drive circuit 13, for example, the light emitting element 7 is first driven to emit the light beam 17, and then the light emitting element 9 is driven to emit the light beam 19. The light emitting element 11 is then driven to emit the light beam 21, and the same operation is repeated thereafter. As a result, when the light emitting element 7 is driven and the light beam 17 is emitted, the light receiving lens 2
When the reflected light is received by the light receiving element 27 via the light beam 17, it can be seen that a reflector exists in the direction in which the light beam 17 is radiated. In a device that sequentially scans a light beam in this way, it is also possible to detect the direction in which the reflector exists, so when detecting a preceding vehicle, it is possible to detect whether the preceding vehicle is transmitting light on the same light transmission lane as the own vehicle. There is an advantage that it is also possible to detect whether or not the preceding vehicle is present. However, in the past, most of the sequential scanning methods were mechanical and had reliability problems, but with the structure of this embodiment, there are no mechanical moving parts, so it is reliable. can improve sexual performance.

In the above embodiment, the case where there are three light emitting elements is described, but it goes without saying that this number may be any number. Furthermore, the light beams emitted from the light emitting elements 7, 9.degree. 11 through the condensing lens 15 can be made into any shape, whether circular or rectangular, by changing the lenses.

FIG. 2 shows another embodiment of the invention.

The optical distance measuring device shown in the figure is the same as the device shown in FIG. 1 except that it has a light emitting section 31 that integrates multiple light emitting elements, The distance circuit 5 and the like are omitted.

The light emitting section 31 is composed of, for example, one integrated chip, and includes a plurality of light emitting elements 7=, 9', and 11- in this embodiment, each consisting of a light emitting diode or a laser diode. have. This light emitting element 7'
, 9', and 11 are driven by a drive circuit 13 as in the case of FIG. 1, and emit light beams 17'', 19', and 21-, respectively.

With this configuration, the intervals between the light emitting elements 7, 9'', and 11' in the light emitting section 31 can be formed very short, and the size can be reduced, and the angular difference between each light beam can be reduced. Δθ can also be made smaller, allowing each light beam to be more closely spaced.Furthermore, the distance between the condenser lens 15 and the light emitting element can be shortened, making the light transmitter 1 much smaller. It has the advantage of being able to be converted into

Note that in each of the above embodiments, the condenser lens 15 is composed of one convex lens, but the present invention can also be applied to a system in which a plurality of lenses are combined in series to constitute one lens system. It is something.

C. Effects of the invention] As explained above, according to this invention, multiple charging r
Since the light emitted from the A source is condensed by one lens system and radiated in a predetermined direction, multiple lenses are not required as in the past, making the device configuration simpler and more compact. and economicalization of equipment can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an optical distance measuring device showing one embodiment of the present invention, and FIG. 2 is a block diagram of essential parts of an optical ranging device showing another embodiment of the present invention.

Claims (1)

[Claims] An optical distance measuring device that emits light, receives reflected light from a reflector, and measures the distance to the reflector based on the propagation delay time from the emission of the light to the reception of the reflected light. What is claimed is: 1. An optical ranging device comprising: a plurality of light radiation sources that emit light; and a lens system that focuses the light emitted from the plurality of light radiation sources in a predetermined direction.