JP2002286844A - Distance measuring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distance measuring equipment that can exhibit the function of a light emission monitor, light reception monitor, contamination monitor, etc., when a simple optical system is added to the equipment. SOLUTION: In the internal upper part of an enclosure 31, a laser diode 5, a light emitting lens 5, a pair of mirrors 21a and 21b, and a projecting window 11 are arranged from the rear side to the front side of the enclosure 31 as the light emitting system of a transmitting-receiving section 1. A window member 35 composed of a transparent cover is put in the window 11. In the enclosure 31, in addition, a transparent light receiving cover 37, a light receiving lens 17, a photodiode 19, and a light receiving circuit 39 are provided on a light receiving substrate 41 as a light receiving system. Particularly, a pair of left and right communicative holes 45 is provided obliquely through a cylindrical member 43 and light guiding members 47 which guide received laser light are respectively inserted into the holes 45 so that the members 47 may pass through the holes 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device mounted on a vehicle, for example, for measuring a distance from a preceding vehicle or the like by light waves.

[0002]

2. Description of the Related Art Conventionally, as a distance measuring device mounted on a vehicle, for example, a device (laser radar) for measuring a distance to an obstacle such as a preceding vehicle using a laser beam is known. This distance measuring device emits a laser diode intermittently and irradiates the front of the vehicle, detects reflected light from an obstacle in front with a photo sensor, and detects an obstacle based on a time difference between a light emitting time and a light receiving time. This is a device that measures the distance to an object.

In the above distance measuring device, in order to detect an abnormality or a failure of the device, for example, a light emitting monitor for monitoring an operating state of a light emitting circuit including a laser diode and an operating state of a light receiving circuit including a photo sensor are monitored. A light receiving monitor to monitor is used. Also, apart from this,
If the glass on the window from which the laser beam is emitted is contaminated, accurate measurement of the distance is not possible, so a dirt monitor for monitoring the dirt condition of the glass is also known.

As the light emission monitor, a dedicated monitor light receiving element for receiving laser light emitted from a laser diode is provided separately from a photosensor for ordinary distance measurement, and a light receiving element for the monitor is provided. In some cases, an abnormality in the light emitting circuit (whether or not light is actually emitted) is detected depending on the light receiving state.

As the light receiving monitor, a dedicated monitor light emitting element (for example, an LED) is provided separately from a laser diode (for normal distance measurement).
In some cases, an abnormality in the light receiving circuit is detected depending on whether or not light from the light is received normally. Further, as the dirt monitor, a dedicated light emitting element (for example, an LED) for the monitor is provided separately from the laser diode (for normal distance measurement), and the dirt is removed based on the reflection of the light emitted from the LED. Some perform detection.

[0006]

However, the above-described technology has the following problems, and further improvements have been demanded. That is, the number of components is reduced when a monitor-dedicated light-emitting element is provided as an emission monitor, when a monitor-dedicated light-emitting element is provided as a light-receiving monitor, and when a monitor-dedicated light-emitting element is provided as a dirt sensor. There has been a problem that the manufacturing process is complicated and the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a distance measuring device capable of exhibiting functions such as a light emission monitor, a light reception monitor, and a dirt monitor by adding a simple optical system. Aim.

[0008]

Means for Solving the Problems and Effects of the Invention (1) According to the first aspect of the present invention, a light emitting means (for example, a light emitting element; a laser diode) for emitting a search light (for example, a laser beam) and a search light are emitted. A window (for example, an exit window) and a light receiving unit (for example, a light receiving element: a photodiode) for receiving reflected light of the search light, and a distance for measuring a distance to a reflecting object based on the reflected light received by the light receiving unit; It relates to a measuring device.

According to the present invention, the window is provided with a window member that transmits the search light and reflects or scatters a part of the search light, and receives the light reflected or scattered by the window member inside the window. A light guiding means (for example, a light guiding member made of an optical fiber) is disposed. Then, one end (for example, an input end) of the light guide means is brought close to or in contact with the window member to face the inner surface of the window member, and the other end (for example, the output end) of the light guide means is connected to the window member. It is opposed to the light receiving means.

According to the present invention, when the search light is emitted from the window, the light reflected and scattered by the window member (reflected scattered light) is introduced into the light guiding means and guided to the light receiving means. it can. Therefore, if the reflected light can be detected by the light receiving means when the search light is emitted, the light emitting system and the light receiving system of the distance measuring device are normal, for example, the light emission of the search light and the light reception by the light receiving means can be performed without failure. It can be seen that this is being done reliably.

That is, unlike the related art, even if a light receiving element or a light emitting element is not separately provided, an abnormality of the distance measuring device can be detected by adding a simple optical system called a light guiding means. (2) According to the second aspect of the present invention, a pair of light guide members are disposed on the left and right sides of the window member or a pair of light guide members are disposed on the upper and lower sides of the window member.

Thus, it is possible to more accurately detect an abnormality in the light emitting system and the light receiving system of the distance measuring device. In particular, when the pair of light guide members are disposed on both sides in the scanning direction of the search light, it is not only understood that the emission of the search light or the reception of light by the light receiving means is performed, but also that the search light However, it can also be detected whether or not the scanning is correctly performed in the scanning direction (for example, the horizontal direction or the vertical direction).

(3) In the invention of claim 3, the light guide member is
A transparent light guide for guiding light incident from one end thereof to the light receiving means side, and a transparent cladding layer having a lower refractive index than the transparent light guide and covering the outer periphery of the transparent light guide are provided. The present invention
2 illustrates a configuration of a light guide member. Thus, light introduced from one end of the light guide member can be efficiently guided to the other end.

(4) According to the invention of claim 4, the end surface of one end of the light guide member is parallel to the inner side surface of the window member.
One end of the light guide member is cut obliquely. In the present invention, since the end surface of one end of the light guide member is parallel to the inner surface of the window member, light reflected and scattered on the inner surface of the window member enters the inside of the light guide member from one end. It becomes easy to light.

(5) In the invention of claim 5, the other end of the light guide member is obliquely cut so that the end surface of the other end of the light guide member is parallel to the light receiving surface of the light receiving member. I have. In the present invention, since the end surface of the other end of the light guide member and the light receiving surface of the light receiving member are parallel, light emitted from the other end of the light guide member is received by the light receiving member without waste. Become.

(6) According to the invention of claim 6, the end surface of the light guide member cut obliquely at one end or the other end is mirror-finished. Accordingly, the light scattered at one end or the other end of the light guide member is reduced, so that even if the amount of light reaching the light guide member is small, it is possible to reliably detect the abnormality of the device.

(7) According to the seventh aspect of the present invention, a transparent film that reflects or scatters light is attached to a portion of the inner surface of the window member where one end of the light guide member faces. Thus, even when the light transmittance of the window member is high, it is possible to detect an abnormality of the apparatus using the light reflected and scattered by the transparent film.

(8) According to the invention of claim 8, one end of the light guiding means is arranged outside the scanning range of the search light for scanning to measure the distance and in the vicinity of the scanning range. Thus, the light guide means is preferable because it does not hinder ordinary distance measurement.

(9) In the ninth aspect of the present invention, when the light receiving surface of the light receiving means has a divided light receiving area capable of receiving light for each area, the other end of the light guide member faces the predetermined divided light receiving area. It is arranged. The present invention exemplifies a case where the light receiving means is constituted by, for example, a large number of light receiving elements (photodiodes). In this case, when light is applied to a specific light receiving element facing the other end of the light guide member and an appropriate output is obtained, it is understood that the device is normal.

(10) In the tenth aspect of the present invention, the distance measuring device includes first monitor means for detecting an abnormality of at least one of the light emitting means and the light receiving means based on the light guided by the light guide member. ing. In the present invention, the first monitor means has some difference (for example, the intensity is low) in the intensity of the light guided by the light guide member as compared with the intensity of the light when the device is normally normal. ),
It can be determined that there is an abnormality in at least one of the light emitting unit and the light receiving unit.

Incidentally, the first monitor means (for example, a light emission monitor and a light reception monitor) can be realized by a program stored in a microcomputer, for example. (11) In the eleventh aspect, the first monitor means includes a light-emitting means and a light-receiving means, when the light guided to the light-receiving means by the light-guiding means is equal to or less than a predetermined first determination value. It is determined that there is an abnormality.

The present invention exemplifies a judgment method using the first judgment value. (12) In the twelfth aspect, the distance measuring device includes the second monitor means for detecting the state of dirt on the surface of the window member based on the light guided to the light receiving means by the light guiding means.

In the present invention, the intensity of the light guided by the light guide member by the second monitoring means has some difference (for example, the intensity of the light when the window member has little contamination). If the strength is determined to be high, it can be determined that a large amount of dirt is attached to the window member.

The second monitor means (for example, a dirt monitor)
Can be realized by, for example, a program stored in a microcomputer. (13) According to the thirteenth aspect, the second monitor means determines whether the surface of the window member is dirty when the light guided to the light receiving means by the light guide means is equal to or greater than a predetermined second determination value. It is determined that it is equal to or greater than a predetermined value.

The present invention exemplifies a judgment method using the second judgment value. (14) In the fourteenth aspect, the distance measuring device is a device mounted on the vehicle and measures the distance to an object ahead of the vehicle by a light wave. The present invention shows that the distance measuring device is a device such as a laser radar used by being mounted on a vehicle.

Thus, since the distance to the object ahead of the vehicle can be known, various vehicle controls such as tracking control can be performed.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a distance measuring apparatus according to the present invention will be described below in detail with reference to the drawings using examples (embodiments). (Embodiment) The distance measuring apparatus of this embodiment is a laser radar which is mounted on a vehicle and can detect an obstacle such as a preceding vehicle ahead.

A) First, the system configuration of the laser radar of this embodiment and its basic operation will be described. As shown in FIG. 1, the laser radar according to the present embodiment includes a transmission / reception unit 1 having a laser light emission system and a light reception system, and a calculation unit 3 for performing various calculation processes and the like as main components as follows. It is configured.

The transmission / reception unit 1 includes a laser diode 5 for generating pulsed laser light (exploration light) as its light emitting system.
, A light emitting lens 7 for condensing the laser light, and a light emitting lens 7
And a projection window 11 for transmitting the light reflected by the scan mirror 9 and emitting the light forward.

The laser diode 5 is connected to the calculation unit 3 via a laser drive circuit 13 and emits a laser beam according to a drive signal from the calculation unit 3. Further, the scan mirror unit 9 is provided with a pair of mirrors 21 (only one swing mirror 21 a is shown in the figure), and a drive signal from the calculation unit 3 is input via the mirror drive unit 15. Then, the swing mirror 21a swings in a predetermined direction by the electromagnetic force.

Thus, the laser beam is irradiated (scanned) in a predetermined angle on a horizontal plane in front of the vehicle (left side in the figure). Further, the transmitting / receiving unit 1
Includes, as its light receiving system, a light receiving lens 17 for receiving a laser beam reflected by an obstacle in front, and a photodiode 19 for receiving light from the light receiving lens 17 and outputting a voltage corresponding to the intensity thereof. .

The output voltage of the photodiode 19 is
After being amplified by a predetermined level through the STC circuit 21, it is input to the variable gain amplifier 23. This variable gain amplifier 2
3 is connected to the arithmetic unit 3 via the A / D converter 25, amplifies the input voltage according to the gain (gain) specified by the arithmetic unit 3, and outputs the amplified voltage to the comparator 27.

The comparator 27 includes a variable gain amplifier 23
Is compared with a threshold value V0, and when V> V0, a predetermined reflected light arrival signal is output to the time measurement circuit 29. The start pulse PA, which means that a drive signal has been output from the calculation unit 3 to the laser drive circuit 13, is also input to the time measurement circuit 29.

Then, the time measuring circuit 29 sets the reflected light arrival signal as the stop pulse PB and the two pulses PA, P
The phase difference of B (that is, the input time difference) is encoded into a binary digital signal, and the value is input to the arithmetic unit 3. This operation unit 3
Is a microcomputer having a well-known CPU, ROM, RAM, and the like. Among them, the ROM stores an arithmetic expression and the like for calculating a distance to an obstacle.

Therefore, the arithmetic unit 3 can determine the distance to the obstacle based on the binary digital signal indicating the input time difference, taking into account data from the vehicle speed sensor and the like.
Basically, (laser beam speed) x (input time difference)
The distance from the obstacle can be determined by the formula: / 2.

B) Next, an optical configuration which is a main part of the laser radar according to this embodiment will be described. As shown in FIGS. 2 and 3, the transmission / reception unit 1 is housed in a substantially rectangular parallelepiped housing 31. A laser diode 5, a light-emitting lens 7, a pair of mirrors 21a and 21b, and a projection window 11 are arranged from the left side (in both figures) to the front.

The laser diode 5 is mounted on a light emitting substrate 33 (FIG. 3) on which the laser drive circuit 19, the mirror drive circuit 15, the operation section 3 and the like are arranged.
Further, of the pair of mirrors 21a and 21b, the fixed mirror 21b is fixed so that its reflection angle does not change, and the oscillating mirror 21a is rotated about the vertical axis so that its reflection angle can be changed. It is provided so as to be able to swing by electromagnetic force.

The projection window 11 is fitted with a window member 35 which is a transparent cover. The window member 35
Transmits most of the laser light, but some of the laser light
The light is reflected and scattered on an inner surface 35c of the inner surface 34a and the outer surface 35b (see FIG. 6).

A light receiving system is provided inside the housing 31 below the above-described light emitting system. The light receiving system is arranged from the front of the housing 31 (to the right in both figures) to the rear. Transparent light receiving cover 37, light receiving lens 17, photodiode 1
9 and a light receiving substrate 41 having a light receiving circuit 39 are arranged. The light receiving circuit 39 includes the STC circuit 21, the variable gain amplifier 23, the A / D converter 25, the comparator 27, the time calculation circuit 29, and the like.

Of these, as shown in FIG.
7 and a light receiving substrate 41 are cylindrical members 43 having tapered through holes 43a so as to cover the periphery of the light path of the light receiving system.
Attached to. In other words, the light receiving lens 1 is provided on the front side of the cylindrical member 43 so as to coincide with the axial center of the through hole 43a.
7 is mounted, and a photodiode 19 is disposed at a position on the rear side where the reflected light passing through the light receiving lens 17 is received.

Particularly, in this embodiment, a pair of left and right communication holes 45 are provided so as to penetrate the cylindrical member 43 obliquely and communicate the light emitting system on the upper part of the housing 31 and the light receiving system on the lower part of the housing 31. A light guide member 47 for guiding the received laser light is inserted through the communication hole 45.

C) Next, the light guide member 47 will be described. First, the configuration of the light guide member 47 itself will be described. As shown in FIG. 4A, the light guide member 47 is a columnar (rod-shaped) transparent optical fiber having a diameter of about 1 mm, and both ends thereof are obliquely cut. That is, the light guide member 47
One end (input end) 47a where the laser light enters and the other end (output end) 47b where the laser light exits are cut so as to be parallel to each other, for example, so as to have a predetermined inclination with respect to the axis center. ing.

The refractive index n1 for guiding the laser light (that is, forming a transparent light guide path) is provided on the center side of the light guide member 47.
A transparent core member 47c (for example, 1.5) is disposed, and the entire outer peripheral surface of the core member 47a is provided with a refractive index n2 (for example, 1.2).
The transparent cladding layer 47d of 4) is formed.

Next, the mounting position of the end of the light guide member 47 will be described. The input end 47a of the light guide member 47 is, as shown in FIG.
In the lower part of the window member 35, close to the window member 35 (for example, 1
mm interval), the inner surface 35a of the window member 35
And are arranged in parallel.

More specifically, as shown in FIG. 5, the input end 47a of the light guide member 47 is arranged outside the scanning range of the laser light (projection light) and close to the scanning range. Particularly, in the present embodiment, a transparent film 49 is attached to the inner side surface 35a of the window member 35 facing the input end 47a of the light guide member 47. The transparent film 49 has a property of easily scattering laser light.
Is arranged so as to slightly overlap the scanning range of the laser beam.

Note that the output end 47b of the light guide member 47 is also
As shown in (2), it is arranged above the photodiode 19, close to the photodiode 19 (for example, at an interval of about 1 mm), and in parallel with the surface of the photodiode 19. Next, the function of the light guide member 47 will be described.

As shown in FIG. 6A, when the laser beam passes through the window member 35, a part of the laser beam is transferred to the interface between the window member 35 and the outside world, that is, the inner surface 35a and the inner surface 35a of the window member 35. The light is reflected and scattered on the inner surface 35c of the outer side surface 35b. A part of the reflected and scattered light (reflected scattered light)
7, and enters the light guide member 47 from the input end 47a. The light that has entered the light guide member 47 is guided while being reflected in the core member 47c due to the characteristics of the optical fiber, and reaches the output end 47b.

At this time, the coupling efficiency of the reflected and scattered light in the window member 35 to the light guide member 47, that is, the ratio indicating how much of the reflected and scattered light is guided into the light guide member 47 is determined by the light guide member 47. And the refractive index difference Δn between the air and the surrounding air.
That is, as shown in FIG. 6B, when the refractive index of the light guide member 47 is n1, the difference in the refractive index is “Δn = n−1”. Only a part of the reflected scattered light having an angle θ between the perpendicular to the end 47 a and “θ = arcsin (Δn)” is guided (coupled) into the light guide member 47.

For example, the refractive index n1 of the light guide member 47 is 1.5.
In this case, “θ = arcsin (0.5)”, so that only the reflected and scattered light having an incident angle θ ≦ 30 ° is coupled to the light guide member 47. Therefore, as shown in FIG.
The scattered light reflected by the window member 35 is coupled to the light guide member 47 only when the laser light passes through the proximity region where the light guide member 47 is disposed. It can be seen that the photodiode 19 and the like are operating normally.

Further, as shown in FIG.
When dirt such as mud adheres to the outer surface 35b of the light guide member 47, the reflectance on the inner surface 35c changes (usually increases). Thus, the state of the stain on the window member 35 can be detected.

D) Next, the processing of the light emission / light reception monitor and the dirt monitor performed by the arithmetic unit 3 using the function of the light guide member 47 and the like will be described. First, processing as a light emission / light reception monitor will be described with reference to the flowchart of FIG.

As shown in FIG. 7, in step 100, a process of outputting a control signal for irradiating the laser drive circuit 13 with laser light is performed. As a result, laser light is emitted from the laser diode 5 to the scanner mirror unit 9 via the light emitting lens 7.

Next, at step 110, a control signal for swinging the swing mirror 21a is output to the mirror driving unit 15. As a result, the oscillating mirror 21a oscillates within a predetermined range, so that the laser light is
The laser light reflected by the oscillating mirror 21a via the mirror moves right and left within a predetermined scanning range.

Next, at step 120, the swing mirror 2
It is determined whether or not the timing at which the laser beam reflected at 1a reaches the limit of the scanning range as shown in FIG.
Here, if the determination is affirmative, the process proceeds to step 130, while if the determination is negative, the process ends once.

In step 130, the photodiode 1
It is determined based on the output voltage from the light receiving circuit 39 whether or not the laser light having a predetermined intensity or higher has entered the light receiving circuit 9. That is, the first
It is determined whether an output voltage equal to or greater than the determination value has been obtained. If the determination is affirmative, the process proceeds to step 140, whereas if the determination is negative, the process proceeds to step 150.

That is, when the light emitting system and the light receiving system (laser diode 5, photodiode 19, etc.) are normal,
Since an output voltage equal to or higher than a predetermined voltage is generated from the light receiving circuit 39, an abnormality in the light emitting system and the light receiving system can be detected based on the output voltage. In step 140, since an appropriate output voltage has been obtained, the light emitting system and the light receiving system are regarded as normal, a normal flag indicating that fact is set, and the present process is ended once.

On the other hand, in step 150, since an appropriate output voltage could not be obtained, it is considered that there is an abnormality in the light emitting system and the light receiving system, an abnormality flag indicating the abnormality is set, and this processing is temporarily terminated. I do. Thereby, the abnormality of the light emitting system and the light receiving system can be accurately detected.

Next, the processing as a dirt monitor will be described with reference to FIG.
A description will be given based on the flowchart of FIG. As shown in FIG. 8, in step 200, a process of outputting a control signal for irradiating laser light to the laser driving circuit 13 is performed.

Next, at step 210, a control signal for swinging the swing mirror 21a is output to the mirror driving unit 15. Next, in step 220, it is determined whether or not the timing at which the laser light reflected by the oscillating mirror 21a reaches the limit of the scanning range. Here, if the determination is affirmative, the process proceeds to step 230, whereas if the determination is negative, the process is temporarily terminated.

In step 230, the photodiode 1
It is determined based on the output voltage from the light receiving circuit 39 whether or not the laser light having a predetermined intensity or higher has entered the light receiving circuit 9. That is, it is determined whether or not an output voltage equal to or greater than the second determination value that exceeds the first determination value is obtained. If a positive determination is made here, step 2
The routine proceeds to 40, while if a negative determination is made, the routine proceeds to step 250.

In step 240, since the output voltage is indicative of the adhesion of dirt of a predetermined level or more, it is considered that the dirt has considerably adhered, and a dirt adhesion flag indicating the fact is set, and this processing is once ended. On the other hand, in step 250, since the output voltage does not indicate the adhesion of the stain that is equal to or more than the predetermined value, it is considered that the stain is little attached, a stain non-adhesion flag indicating that fact is set, and the process is once ended.

Thus, it is possible to recognize the adhesion state of dirt on the projection window 11. e) As described above, in the present embodiment, the light guide member 47 made of an optical fiber is disposed on the path from the window member 35 to the photodiode 19, and the laser light reflected and scattered by the window member 35 is applied to the photodiode 19. I try to guide.

As a result, when laser light having a predetermined intensity or more enters the photodiode 19 at an appropriate timing, it can be understood that the light emitting system and the light receiving system of the laser radar are normal. In addition, when excessive laser light is incident on the window member 35, it is understood that the window member 35 is contaminated.

That is, according to the present embodiment, the light guide member 47
With the addition of the simple optical system, there is a remarkable effect that functions as a light emission / light reception monitor and a dirt monitor can be realized. Further, in the present embodiment, the presence or absence of the reception of the laser light is determined at the timing when the laser light is scanned right and left, so that it is possible to detect whether the scanning of the laser light is appropriately performed.

It is needless to say that the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the technical scope of the present invention. (1) For example, as the shape of the light guide member, FIG.
Other shapes as shown in (b) to (d) can be adopted. Among them, FIG. 4B does not include a transparent cladding layer on the outer periphery of the core member of the light guide member. FIG. 4 (c)
Has a transparent cladding layer formed on the light guide member,
Both ends are cut vertically. Further, FIG.
(D) does not include a transparent cladding layer on the outer periphery of the core member of the light guide member, and has both ends of the light guide member cut vertically.

(2) In the above embodiment, the positions of the input end and the output end of the light guide member are set near the window member and the end of the photodiode so as not to hinder the normal operation of distance measurement. Although it is arranged, it can be arranged at an arbitrary position so as to face the window member or the photodiode as long as the distance can be measured.

(3) Further, in the above embodiment, the input end and the output end of the light guide member are slightly separated from the window member and the photodiode, but may be in contact with them. For example, even when the input end is brought into contact with the window member, the incident amount of the reflected scattered light is reduced, but the function of the monitor can be sufficiently exhibited.

(4) In the above-described embodiment, the abnormality and dirt of the light emitting system and the light receiving system are detected by the operation accompanying the scanning of the laser beam in the normal distance measurement. The scanning of the same laser beam may be performed once or plural times at a unique timing only for the purpose of detecting.

(5) Further, the detection of the abnormality of the light emitting system and the light receiving system and the detection of the contamination may be performed separately.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an entire laser radar system according to an embodiment;

FIG. 2 is an explanatory diagram illustrating a configuration of a light emitting system and a light receiving system of the laser radar according to the embodiment.

FIG. 3 is a cross-sectional view showing a housing for housing a light emitting system and a light receiving system of the laser radar according to the embodiment and an internal configuration thereof.

FIG. 4 is an explanatory view showing a conductive member.

FIG. 5 is a perspective view showing an arrangement of one end of a conductive member, a window member, and the like.

FIG. 6A is an explanatory diagram showing a state of light in a window member, and FIG. 6B is an explanatory diagram showing a state of light introduced into a conductive member.

FIG. 7 is a flowchart illustrating processing of a light emission / light reception monitor according to the embodiment.

FIG. 8 is a flowchart illustrating a dirt monitor process according to the embodiment.

[Explanation of symbols]

 1. Transmitter / receiver unit 3. Operation unit 5. Laser diode 7. Light emitting lens 11. Emission window 17. Light receiving lens 19. Photodiode 35 Window member 47 Light guide member

Continued on the front page F term (reference) 5J084 AA01 AA05 AB17 AD01 BA04 BA36 BA49 BB01 BB21 BB31 CA03 CA23 CA49 EA17 EA20 EA31 FA01

Claims (14)

[Claims] 1. A light emitting means for emitting a search light, a window for emitting the search light, and a light receiving means for receiving a reflected light of the search light, based on the reflected light received by the light receiving means. In a distance measuring device that measures a distance to a reflective object, a window member that transmits the search light and reflects or scatters a part thereof is disposed in the window, and the window is provided inside the window. A light guide means for receiving and guiding light reflected or scattered by the member is provided, and further, one end of the light guide means is brought into contact with the window member or in contact with the window member to form an inner surface of the window member. A distance measuring device, wherein the other end of the light guide means faces the light receiving means. 2. The distance measuring apparatus according to claim 1, wherein a pair of the light guide members is arranged on the left and right of the window member or a pair of the light guide members is arranged on the upper and lower sides of the window member. 3. The light guide member includes: a transparent light guide for guiding light incident from the one end to the light receiving unit; and a transparent clad having a lower refractive index than the transparent light guide and covering an outer periphery of the transparent light guide. The distance measuring device according to claim 1, further comprising a layer. 4. The light guide member according to claim 1, wherein one end of the light guide member is obliquely cut such that an end surface of one end of the light guide member is parallel to an inner surface of the window member. 1
The distance measuring device according to any one of claims 1 to 3. 5. The light guide member according to claim 1, wherein the other end surface of the light guide member is obliquely cut such that an end surface of the other end of the light guide member is parallel to a light receiving surface of the light receiving member. The distance measuring device according to claim 1. 6. The distance measuring apparatus according to claim 4, wherein a mirror surface is applied to a surface of the obliquely cut end. 7. A transparent film, which reflects or scatters light, is attached to a portion of the inner surface of the window member where one end of the light guide member faces.
7. The distance measuring device according to any one of claims 6 to 6. 8. The apparatus according to claim 1, wherein one end of said light guide means is arranged outside a scanning range of a search light for scanning to measure said distance and in the vicinity of the scanning range.
The distance measuring device according to any one of the above. 9. When the light receiving surface of the light receiving means has a divided light receiving region capable of receiving light for each region, the other end of the light guide member is arranged to face the predetermined divided light receiving region. The distance measuring device according to any one of claims 1 to 8, wherein: 10. The apparatus according to claim 1, wherein the distance measuring device includes a first monitor for detecting an abnormality of at least one of the light emitting unit and the light receiving unit based on the light guided to the light receiving unit by the light guiding unit. The distance measuring device according to any one of claims 1 to 8, characterized in that: 11. The first monitoring means, if the light guided to the light receiving means by the light guiding means is equal to or less than a predetermined first judgment value, at least one of the light emitting means and the light receiving means has an abnormality. 11. The distance measuring device according to claim 10, wherein it is determined that there is a distance. 12. The distance measuring device further comprises a second monitor for detecting a state of dirt on a surface of the window member based on light guided to the light receiving unit by the light guiding unit. The distance measuring device according to any one of claims 1 to 11, which performs the distance measurement. 13. When the light guided by the light guide means to the light receiving means is equal to or more than a predetermined second determination value, the second monitor means sets a state of dirt on the surface of the window member equal to or more than a predetermined value. 13. The distance measuring apparatus according to claim 12, wherein the distance is determined. 14. The distance according to claim 1, wherein the distance measuring device is mounted on a vehicle and measures a distance to an object ahead of the vehicle by a light wave. measuring device.