JPH07134178A - In-vehicle distance measuring device using laser light - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to perform appropriate measurement by controlling the emission power of laser light according to the situation, avoid adverse effects on the human body, and suppress deterioration of the emission part. An object of the present invention is to provide a vehicle-mounted distance measuring device using laser light. [Constitution] In recent years, a vehicle-mounted distance measuring device has been proposed which measures a distance to a measurement target based on a delay time until a laser beam is emitted and reflected light from the measurement target is received. Regarding the emission of this laser light, as shown in FIG. 1A,
The light emission power is controlled based on the distance to the measurement target, the traveling speed of the vehicle, etc. (FIG. 2B). As a result, it is possible to avoid the adverse effect of the laser light on the human body. Further, the irradiation range of laser light can be expanded to reduce the energy density of laser light. Further, it is possible to irradiate the irradiation range of the laser light with visible light or selectively limit the irradiation range to avoid adverse effects on the eyes and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted distance measuring device using a laser beam, and more particularly to a structure for preventing a laser beam from adversely affecting a human body.

[0002]

2. Description of the Related Art In recent years, other vehicles traveling in front of an automobile,
An on-vehicle distance measuring device that detects an obstacle has been proposed. The distance measuring device measures a distance to another vehicle or an obstacle located in front of the vehicle, and when the measured distance becomes short, for example, an alarm sound is emitted as a danger of a rear-end collision.

A vehicle 100 shown in FIG. 10 is equipped with a distance measuring device, and a laser beam L1 is emitted from a light emitting section H1 of the distance measuring device. This laser light L1 is scanned in the direction of arrow 90, and the measurement target vehicle 101 traveling in the front direction.
Is irradiated. The laser light L1 is reflected by a reflector provided at the rear part of the vehicle to be measured 101, and the reflected light is received by a light receiving unit (not shown) of a distance measuring device mounted on the automobile 100. The distance measuring device measures the vehicle 101 to be measured based on the delay time from the light emission to the light reception of the laser beam L1.
Calculate the distance to.

[0004]

The conventional in-vehicle distance measuring device has the following problems. The laser light L1 from the automobile 100 is always emitted with a constant energy density. Here, the energy density refers to the amount of energy supplied to a unit area per unit time. This energy density needs to be set to a certain degree high in order to secure a sufficient measurement distance.

However, if the energy density is too high,
For example, water droplets or dirt attached to the protective glass of the light emitting portion H1,
Raindrops may be detected. On the contrary, if the energy density is set low, a sufficient measurement distance cannot be secured. As described above, the conventional vehicle-mounted distance measuring device has a problem that proper measurement cannot be performed because the laser light is constantly emitted with a constant energy density.

The laser light may adversely affect the human body such as eyes and skin depending on the light quantity and irradiation time. Laser light L1 from the automobile 100 is measured by the vehicle 1
There is also a problem in that the light is reflected by the rearview mirror No. 01 and damages the human body such as the eyes of the occupants and pedestrians of the measurement target vehicle 101. In particular, when the distance between the automobile 100 and the measurement target is short or when the irradiation time of the laser light L1 to the measurement target is long, the risk is high. Furthermore, since the energy density of the laser light L1 is at a constant level, the laser diode is severely deteriorated and the product life is shortened.

There is a method in which the emission of the laser beam L1 is stopped when the traveling speed of the automobile falls below a certain reference, for example, 30 km / h. This is intended to prevent the frequency of warning sounds emitted based on the inter-vehicle distance from increasing, and to prevent a reduction in attention to the warning sounds due to habituation. In such a device, since the laser beam is stopped when the traveling speed becomes lower than the reference speed, the above-mentioned problems caused by constantly emitting light are alleviated.

However, when the traveling speed exceeds the reference speed, laser light of a constant energy density is emitted, and the above problems cannot be said to be sufficiently solved. Further, in this device, the generation of the alarm sound is also stopped at the same time as the laser light is stopped, which causes a problem.

Therefore, according to the present invention, the laser can be appropriately measured by controlling the energy density of the laser light depending on the situation, the adverse effect on the human body can be avoided, and the deterioration of the light emitting portion can be suppressed. An object is to provide an on-vehicle distance measuring device using light.

[0010]

According to a first aspect of the present invention, there is provided a vehicle-mounted distance measuring device using a laser beam, which emits a laser beam toward an object to be measured and receives reflected light of the laser beam from the object to be measured. In a vehicle-mounted distance measuring device using a laser beam, which includes a light receiving unit that outputs a light receiving signal and a distance measuring unit that measures and outputs a distance to a measurement object based on the light receiving signal from the light receiving unit, Vehicle speed detection unit that detects and outputs the vehicle speed, or a relative speed detection unit that detects and outputs the relative speed between the vehicle and the measurement target, the distance output by the distance measurement unit and the vehicle speed detection Based on the traveling speed of the vehicle output by the unit, or the relative speed output by the relative speed detection unit and the distance output by the distance measurement unit, depending on the decrease in the distance or the detected speed, from the light emitting unit Laser light energy Control unit for reducing the degrees, it is characterized by comprising a.

A vehicle-mounted distance measuring device using a laser beam according to a second aspect is the vehicle-mounted distance measuring device using a laser beam according to the first aspect, wherein the control unit suppresses the emission power of the laser beam. The feature is that the energy density is reduced.

According to a third aspect of the present invention, there is provided a vehicle-mounted distance measuring device using a laser beam according to the first aspect, wherein the control unit temporally controls the emission of the laser beam. Is characterized by reducing the energy density.

A vehicle-mounted distance measuring device using a laser beam according to a fourth aspect is the vehicle-mounted distance measuring device using a laser beam according to the first aspect, wherein the controller spatially expands the irradiation range of the laser beam. The energy density is thereby reduced.

According to a fifth aspect of the present invention, there is provided an in-vehicle distance measuring device using a laser beam, which comprises a light emitting section for emitting a laser beam toward an object to be measured.
In a vehicle-mounted distance measurement device using a laser beam, the irradiation range of the laser beam is simultaneously irradiated with visible light.

According to a sixth aspect of the present invention, there is provided an in-vehicle distance measuring device using a laser beam, which comprises a light emitting section for emitting a laser beam toward a measuring object.
In a vehicle-mounted distance measuring device using a laser beam provided with, a light-shielding portion that limits the irradiation range by partially blocking the laser light is provided, and the light-shielding portion shields the laser light freely. The feature is that it can be opened.

[0016]

In a vehicle-mounted distance measuring device using a laser beam according to claim 1, a vehicle traveling speed detecting section for detecting and outputting the traveling speed of the vehicle, or a relative speed between the vehicle and an object to be measured is detected. A relative speed detector for outputting is provided. The control unit outputs the distance output by the distance measuring unit, the traveling speed of the vehicle output by the vehicle traveling speed detecting unit, or the distance output by the distance measuring unit, and the relative speed output by the relative speed detecting unit. Based on the above, the energy density of the laser light from the light emitting portion is reduced according to the decrease in the distance or the detected speed.

Therefore, the distance to the measurement object and the traveling speed of the vehicle, or the distance to the measurement object and the relative speed between the vehicle and the measurement object are grasped, and the adverse effect of the laser light on the measurement object is exerted. If there is a possibility that the laser light will occur, the energy density of the laser light can be reduced to avoid an adverse state due to the laser light.

In the on-vehicle distance measuring device using the laser light of the second aspect, the control unit reduces the energy density by suppressing the emission power of the laser light.
Therefore, the deterioration of the light emitting portion can be suppressed more reliably.

In the on-vehicle distance measuring device using the laser beam of the third aspect, the control unit reduces the energy density by temporally controlling the emission of the laser beam. Therefore, the deterioration of the light emitting portion can be suppressed more reliably.

In the vehicle-mounted distance measuring device using the laser light of the fourth aspect, the control unit reduces the energy density by spatially expanding the irradiation range of the laser light. Therefore, the energy density of the laser light can be easily reduced by controlling the optical system in the light emitting unit, for example.

In the on-vehicle distance measuring device using the laser beam of the fifth aspect, the visible range is simultaneously irradiated to the irradiation range of the laser beam. Therefore, when irradiated with the laser light, the light can be visually recognized by the visible light.

According to another aspect of the present invention, there is provided a vehicle-mounted distance measuring device using a laser beam, which is provided with a light-shielding portion for limiting an irradiation range by partially blocking the laser light. It can be blocked and opened freely. Therefore, it becomes possible to arbitrarily limit the irradiation range of the laser light.

[0023]

[Example] A vehicle-mounted distance measuring device using a laser beam irradiates a laser beam toward a measurement target such as another vehicle, a pedestrian, or an obstacle in front, and receives the reflected light to measure the measurement target. Measure the distance. Then, based on the distance to this measurement target,
For example, automatic follow-up operation is performed to maintain a constant vehicle-to-vehicle distance with respect to another vehicle in front, and an alarm is issued to notify the danger of a rear-end collision with the measurement target. Embodiments of a vehicle-mounted distance measuring device using laser light according to the present invention will be described below with reference to the drawings. In the following embodiments, a device that issues an alarm based on the distance to the measurement target is taken as an example.

[First Embodiment] First, FIG. 1 shows a block diagram of a distance measuring apparatus in the first embodiment. In this embodiment, the emission power of the laser light is switched based on the distance to the measurement target, the traveling speed of the vehicle, and the like. As shown in FIG. 1, the control unit 2 includes a light emission control device 4
The light emission of the laser diode 10 is controlled through. The light emission control device 4 and the laser diode 10 are the light emitting unit in the present invention.

In the light emission control device 4, the LD drive section 42,
Light emission power switching control unit 8, light emission on / off control unit 6
Is provided. A signal is given to the LD drive unit 42 from the light emission power switching control unit 8 and the light emission on / off control unit 6, and the LD drive unit 42 outputs a light emission signal to the laser diode 10 in accordance with this signal. And
The laser diode 10 emits laser light based on this light emission signal.

The light emission power switching controller 8 is supplied with a light emission power switching signal from the controller 2. The light emission power switching control unit 8 outputs a light emission signal according to this signal, and the light emission power of the laser light from the laser diode 10 is switched. Further, when the light emission on / off control unit 6 in the light emission control device 4 is given an on / off signal from the control unit 2 and the light emission on / off control unit 6 receives an off instruction, the LD drive unit 42. Control to stop the emission of laser light.

The laser light from the laser diode 10 is
The light is transmitted through the diffusing lens 20 and irradiated onto the measurement target. Then, the laser light is reflected by the object to be measured, the reflected light is condensed by the condenser lens 62, is received by the photodiode 12, and a light reception signal is output. The received light signal output from the photodiode 12 is amplified by the amplifier 40 and taken into the control unit 2. A light receiving sensitivity switching control unit 16 is also provided in the light receiving device 12. Light receiving sensitivity switching control unit 1
Reference numeral 6 receives the light receiving sensitivity switching signal from the control unit 2, changes the amplification factor of the amplifier 40, and switches the light receiving sensitivity of the laser light.

The control unit 2 measures the distance to the measurement object based on the delay time from the emission of the laser light to the reception of the reflected light. Then, when the distance to the measurement target becomes shorter than a predetermined distance, it is determined that there is a danger of a rear-end collision, an alarm signal is output, and an alarm sound is generated from the alarm device 30 to alert the driver. .

The control unit 2 is also provided with a traveling speed signal from a traveling speed detecting unit 32 which is a traveling speed detecting unit of the own vehicle. The control unit 2 adjusts the light emission power of the laser light and the light receiving sensitivity of the light receiving device 14 based on the traveling speed and the distance to the measurement target. The specific content of this adjustment is shown in FIG. FIG. 2A shows the content of control of the laser light according to the distance to the measurement target and the traveling speed. As shown in FIG. 2A, if the traveling speed is 20 km / h or less, the control unit 2 gives a command to the light emission on / off control unit 6 by an on / off signal regardless of the distance to the measurement target (see FIG. 1), turn off the laser light emission.

When the traveling speed is increased and the laser light is turned on, two types of switching control of ON and ON are performed in the example shown in FIG. 2A. ON
2B, the light emission power is set to 1 W to increase the light receiving sensitivity, and ON is control to set the light emission power to 16 W and reduce the light receiving sensitivity. Figure 3
FIG. 4 is a diagram showing the emission power of laser light, and the horizontal axis is the time axis. FIG. 3A shows an ON emission power of 16 W, and FIG. 3B shows an ON emission power of 1 W.

Further, the light receiving sensitivity of this measuring device is adapted to change according to the time from the emission of the laser light to the light reception, that is, the distance to the object to be measured, as shown by the light receiving sensitivity curve M1 in FIG. There is. Then, when the light receiving sensitivity is increased by turning on, set this light receiving sensitivity curve to M2,
To decrease the photosensitivity by turning it on, set the photosensitivity
Set to 3.

As shown in FIG. 2A, in the present embodiment, the traveling speed is 20 km / h, 30 km / h, 40 km /
A boundary for light emission power control is set at h and distances of 15 m and 20 m from the measurement target. In this embodiment, a hysteresis characteristic is provided to prevent chattering that occurs near the boundary.

That is, in FIG. 2A, for example, when the measurement point belongs to the range R1, the laser beam is in the OFF state, and even if the traveling speed increases from this state and the measurement point shifts to the range R2, it follows the hysteresis characteristic. The laser light remains off. Then, when the traveling speed exceeds 30 km / h and the measurement point shifts to the range R3, the laser light is emitted at ON and the light receiving sensitivity is controlled.

Here, even if the speed changes repeatedly near the boundary of the traveling speed of 30 km / h, since it has a hysteresis characteristic, the ON state is maintained and chattering does not occur.

Also, the boundary of the distance from the measurement object is given a hysteresis characteristic so that chattering does not occur. Therefore, for example, even if the distance is repeatedly changed near the boundary between the ranges R3 and R4, the emission power and the light receiving sensitivity are kept stable. Similarly, chattering does not occur at the boundary between the ranges R2 and R4.

As described above, the switching from ON to ON is performed when the two conditions of "there is no measurement target within 20 m" and "the traveling speed is 40 km / h or more" are satisfied at the same time. Conversely, from ON to ON
The switching to is performed when either one of the conditions "the object to be measured is within 15 m" or "the traveling speed is 30 km / h or less" is satisfied. Note that these conditions may be satisfied only when the conditions are continued for a certain period of time, for example, 1 second.

When the distance to the object to be measured is short, the irradiated laser light has a great adverse effect on the human body such as the eyes. Therefore, the emission power of the laser light is lowered and the energy density of the laser light is reduced. Further, when the traveling speed is high, for example, a pedestrian who is irradiated with laser light or another vehicle traveling ahead can be passed in a short time, and the irradiation time to the human body is shortened. Therefore, the emission power of the laser light can be increased. On the other hand, when the traveling speed is slow, on the contrary, the irradiation time to the human body is likely to be long, which may adversely affect. Therefore, similarly, the emission power of the laser light is lowered to reduce the energy density of the laser light. ing.

In this way, the light emission power is lowered according to the distance from the object to be measured and the running speed. Moreover, since the emission power of the laser light is reduced according to the situation such as the distance to the measurement object and the traveling speed, it is possible to perform an appropriate measurement and suppress deterioration of the light emitting unit.

If the light receiving sensitivity remains high when the light emission power is high, for example, reflected light from raindrops will also be received, and there is a risk of erroneous detection. Therefore, ON
When the light emission power is increased by, the light reception sensitivity is set low as described above. On the contrary, when the light emission pattern is lowered by turning it on, inconvenience such as erroneous detection does not occur, so that the light receiving sensitivity can be increased.

In the example of FIG. 2A, when the laser light is turned on, the control is switched between two types of ON and ON, but at the time of this switching, the control of ON and ON (FIG. 2B) is taken into consideration. You may make it switch selectively. That is, when switching from ON to ON, ON, O
When switching from N, ON, ON in this order, and vice versa, when switching from ON to ON, ON, ON, ON, ON
You can also switch in the order of. By switching the light emission power and the light receiving sensitivity stepwise in this manner, it is possible to avoid a sudden change in the detection data.

The boundary values for switching control shown in FIG. 2A are subdivided into OFF, ON, ON, and
It is also possible to add ON and ON to perform multistage switching control. In the above embodiment, the control unit 2 takes in the traveling speed signal from the traveling speed detecting unit 32 and controls it (see FIG. 1). However, instead of the traveling speed, the control can be performed using the relative speed with respect to the measurement target. The relative speed to the measurement target can be obtained by measuring the distance to the measurement target twice or more. When the relative speed to the measurement target is used instead of the traveling speed, the control unit 2 does not need to take in the traveling speed signal from the traveling speed detection unit 32.

[Second Embodiment] Next, a second embodiment will be described. In the first embodiment, the energy density of the laser light is reduced by switching the emission power, but in the present embodiment, the energy density is reduced by temporally controlling the light emission of the laser light. For example, when the laser light of FIG. 3A is used as a reference, the emission cycle of the light emission pulse is widened as shown in FIG. 3C, and the energy density of the laser light is reduced as a whole. Also,
As shown in FIG. 3D, the ON time of the light emission pulse itself may be shortened to reduce the energy density of the laser light. Other methods may be adopted as long as the emission of laser light can be temporally controlled.

[Third Embodiment] Next, a third embodiment of a vehicle-mounted distance measuring device using a laser beam according to the present invention will be described with reference to FIGS. In this example,
By spatially expanding the irradiation range of laser light,
Reduce energy density. If the irradiation range of the laser light is expanded, the energy density in the specific range will be reduced, and the adverse effect on the human body in this specific range can be avoided.

FIG. 5 is a block diagram of the distance measuring device in this embodiment. The control unit 2 is similar to the first embodiment in that
An ON / OFF signal is given to the light emission ON / OFF control unit 6 in the light emission control device 4, and the light emission ON / OFF control unit 6 controls the LD drive unit 42 according to this signal. And L
The D drive unit 42 outputs a light emission signal to the laser diode 10 in accordance with a command from the light emission on / off control unit 6,
Controls the emission or stop of laser light.

In this embodiment, the controller 2 outputs a lens movement signal and moves the diffusion lens 20.
In this embodiment, a collimating lens is used as the diffusing lens 20. As shown in FIG. 6A, the diffusing lens 20 is held by the holding bar 21, and the optical path L2 of the laser light is moved in the directions of arrows 91 and 92 in accordance with the lens movement signal.
It is designed to move up. As the diffusion lens 20 moves, the laser light irradiation range expands. For example, when the diffusion lens 20 is moved in the direction of arrow 92 as shown in FIG. 6B, the laser light irradiation range is from L3 to L4.
Energy density in a specific range is reduced.

A Fresnel lens may be used as another embodiment for spatially expanding the laser light irradiation range. Since this Fresnel lens expands or contracts depending on the temperature, by controlling the temperature given to the lens,
By changing the focal position of the lens, it is possible to freely adjust the spatial expansion of the irradiation range of the laser light. If the irradiation range of the laser light can be expanded,
Other mechanisms may be used.

[Fourth Embodiment] Next, a fourth embodiment of a vehicle-mounted distance measuring device using a laser beam according to the present invention will be described with reference to FIG.
It will be described based on. When the human body is irradiated with the laser light, there is a high possibility that the eyes will be adversely affected.
For example, when another vehicle traveling in front is irradiated with laser light, the laser light is reflected by the rearview mirror, which adversely affects the occupant's eyes. Therefore, in this embodiment, the irradiation range of the laser light is simultaneously irradiated with the irradiation light of the LED. By thus irradiating visible light at the same time, when the irradiation of laser light is received, this irradiation can be visually recognized, and the eyes are diverted from the laser light. Therefore,
It is possible to avoid adverse effects on the human body, especially the eyes, without observing the laser light for a long time.

FIG. 7 is a block diagram of the measuring apparatus in this embodiment. The light emission control device 4 includes an LD drive unit 42, a light emission on / off control unit 6, an LED drive unit 43, and an LED.
The controller 25 is provided. The LED control unit 25 is given an LED control signal from the control unit 2, and the LED control unit 25 gives a command to the LED drive unit 43 based on this signal. Then, the LED drive unit 43 is connected to the LED control unit 2
The LED 26 is caused to emit light in accordance with the command from 5, and the LED irradiation light passes through the lens 66 and is irradiated.

The control unit 2 causes the LED 26 to simultaneously irradiate the irradiation range of the laser light at least while the laser light is being radiated from the laser diode 10. In this way, adverse effects on the human body are avoided. It should be noted that other than LEDs may be used as long as they emit visible light.

[Fifth Embodiment] FIGS. 8 and 9 show the fifth embodiment. FIG. 8A is a front view of an irradiation range L2 of the laser light emitted from the laser diode 10. As shown in the drawing, the laser light is emitted in a vertically long shape and is scanned in the direction of arrow 90 (see FIG. 10). Since the reflected light of the laser light is generated, for example, by being reflected by the reflector 50 of the vehicle to be measured shown in the figure, it is preferable not to irradiate the rearview mirror 51 or the like which may adversely affect the human body.

For this reason, in this embodiment, the irradiation range L2 of the laser light is partially blocked by the light shielding plates F1, F2, F3 as the light shielding portion to limit the irradiation range L2. As shown in FIG. 8B, the light blocking plates F1, F2, and F3 are solenoids N, respectively.
1, N2, N3 are connected, and arrows 95, 9 are freely
It is possible to move in six directions and block or open the irradiation of laser light. Each solenoid has a control unit 2
It drives according to the signal from (refer FIG.1, FIG.5, FIG.7). These light-shielding plates are provided near the laser diode 10.

In order to recognize the position of the reflector in the irradiation range L2, in the present embodiment, each of the light shielding plates F1,
F2 and F3 are sequentially opened to determine the presence / absence of reflected light. A flowchart of this process is shown in FIG. First, a laser beam is scanned once with all the light shielding plates F1, F2, F3 open, and the presence or absence of reflected light is determined (steps S2, S).
4). Then, when the reflected light is received, in order to recognize the position of the reflector, the light shielding plates F1, F2, and F3 are sequentially and selectively opened to perform the measurement operation, and the presence or absence of the reflected light is determined ( Steps S6, S8, S10, S1
2, S14).

In this way, the irradiation range L2 of the laser beam is limited to the range necessary for taking in the reflected light, and the adverse effect on the human body is avoided. The irradiation range may be limited by providing two or four or more light shielding plates. Further, as the light shielding portion, a material other than the light shielding plate shown in this embodiment can be used.

[Other Embodiments] The above embodiments may be arbitrarily combined. For example, the first embodiment, the second embodiment, and the third embodiment may be combined and implemented. Further, a fourth embodiment in which visible light is simultaneously irradiated to a laser light irradiation range can be applied to these embodiments, and a fifth embodiment in which the laser light irradiation range is blocked and limited. It can also be applied.

[0055]

According to the on-vehicle distance measuring device using the laser light of the first aspect, the vehicle traveling speed detecting section for detecting and outputting the traveling speed of the vehicle or the relative speed between the vehicle and the object to be measured. A relative speed detection unit for detecting and outputting is provided.
The control unit outputs the distance output by the distance measuring unit, the traveling speed of the vehicle output by the vehicle traveling speed detecting unit, or the distance output by the distance measuring unit, and the relative speed output by the relative speed detecting unit. Based on the above, the energy density of the laser light from the light emitting portion is reduced according to the decrease in the distance or the detected speed.

That is, the distance to the measurement object and the traveling speed of the own vehicle, or the distance to the measurement object and the relative speed between the own vehicle and the measurement object are grasped, and the adverse effect of the laser light on the measurement object is obtained. If there is a possibility that the laser light will occur, the energy density of the laser light can be reduced to avoid an adverse state due to the laser light.

Therefore, the energy density of the laser light can be controlled according to the situation such as distance and traveling speed. For example, when the distance to the measurement target is long or the traveling speed is fast, it is possible to perform control such as increasing the energy density of the laser light and perform appropriate measurement. Further, when there is a possibility that the laser light adversely affects the measurement target, the energy density of the laser light is reduced, so that the adverse effect on the human body can be avoided. Further, since the laser light is not always emitted with a high energy density, deterioration of the light emitting portion can be suppressed.

In the on-vehicle distance measuring device using the laser light of the second aspect, the control unit reduces the energy density by suppressing the emission power of the laser light.
Therefore, the deterioration of the light emitting portion can be suppressed more reliably.

In the on-vehicle distance measuring device using the laser light of the third aspect, the control unit temporally reduces the energy density of the laser light. Therefore, the deterioration of the light emitting portion can be suppressed more reliably.

In the vehicle-mounted distance measuring device using the laser beam according to the fourth aspect, the control unit reduces the energy density by spatially expanding the irradiation range of the laser beam. Therefore, the energy density of the laser light can be easily reduced by controlling the optical system in the light emitting unit, for example.

The on-vehicle distance measuring device using the laser light of claim 5 irradiates the irradiation range of the laser light with visible light at the same time. That is, when irradiated with laser light, the light can be visually recognized by visible light. Therefore, it is possible to avoid adverse effects on the human body, particularly the eyes, without visually observing the laser light for a long time.

An on-vehicle distance measuring device using a laser beam according to claim 6 is provided with a light-shielding part for limiting the irradiation range by partially blocking the laser light.
The laser light can be blocked and opened freely.
That is, it becomes possible to arbitrarily limit the irradiation range of the laser light. Therefore, for example, it is possible to block the portion of the human body irradiated with the laser light, and avoid adverse effects on the human body.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an in-vehicle distance measuring device using laser light according to the present invention.

FIG. 2A is a diagram showing the content of control of laser light according to the distance to the measurement object and the traveling speed, and FIG. 2B is the ON, ON, ON, ON emission power and light reception sensitivity in FIG. 2A. It is a figure which shows the content of.

FIG. 3 is a diagram showing an emission power of a laser beam and an emission pulse.

FIG. 4 is a diagram showing a light receiving sensitivity curve of light receiving sensitivity in the vehicle-mounted distance measuring device of FIG. 1.

FIG. 5 is a block diagram showing a second embodiment of a vehicle-mounted distance measuring device using laser light according to the present invention.

FIG. 6 is a diagram showing movement of the lens shown in FIG. 2 and expansion of a laser light irradiation range.

FIG. 7 is a block diagram showing a third embodiment of a vehicle-mounted distance measuring device using laser light according to the present invention.

FIG. 8 is a diagram showing a limitation on an irradiation range of laser light.

9 is a flowchart of a process for sequentially opening the light shielding plate shown in FIG.

FIG. 10 is a diagram showing laser light irradiation of a vehicle-mounted distance measuring device.

[Explanation of symbols]

 2 ... Control unit 4 ... Emission control device 6 ... Emission on / off control unit 8 ... Emission power switching control unit 10 ... Laser diode 12. .... Photodiode 14 ... Light receiving device 16 ... Light receiving sensitivity switching control unit 20 ... Diffusing lens 25 ... LED control unit 26 ... LED 32・ ・ ・ Running speed detector F1, F2, F3 ・ ・ ・ ・ ・ Light shield

Claims (6)

[Claims] 1. A light emitting section that emits laser light toward a measurement target, a light receiving section that receives reflected light of the laser light from the measurement target and outputs a light reception signal, and a measurement target based on the light reception signal from the light receiving section. In a vehicle-mounted distance measuring device using a laser beam, the distance measuring unit for measuring and outputting the distance between
Alternatively, a relative speed detection unit that detects and outputs the relative speed between the own vehicle and the measurement target, the distance output by the distance measurement unit and the traveling speed of the own vehicle output by the own vehicle traveling speed detection unit, or the distance measurement unit A control unit that reduces the energy density of the laser light from the light emitting unit according to the distance or the decrease in the detected speed, based on the distance output by and the relative speed output by the relative speed detection unit. An in-vehicle distance measuring device using a laser beam characterized by the above. 2. A vehicle-mounted distance measuring device using a laser beam according to claim 1, wherein the controller reduces the energy density by suppressing the emission power of the laser beam. In-vehicle distance measuring device used. 3. A vehicle-mounted distance measuring device using a laser beam according to claim 1, wherein the control section temporally controls the emission of the laser beam to reduce the energy density. In-vehicle distance measuring device using light. 4. A vehicle-mounted distance measuring device using a laser beam according to claim 1, wherein the control unit spatially expands the irradiation range of the laser beam to reduce the energy density. In-vehicle distance measuring device using laser light. 5. An in-vehicle distance measuring device using a laser beam, which comprises a light emitting portion for emitting a laser beam toward a measurement target, wherein the irradiation range of the laser beam is simultaneously irradiated with visible light. In-vehicle distance measuring device using laser light. 6. A vehicle-mounted distance measuring device using a laser beam, comprising: a light emitting section for emitting a laser beam toward a measurement target; and a light-blocking section for limiting an irradiation range by partially blocking the laser beam. The in-vehicle distance measuring device using laser light, characterized in that the light shielding portion can freely block and open the laser light.