JPH05120904A - Road lighting device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a road lighting device in which obstacles are easy to visually recognize according to the weather and the condition of the road surface and the vehicle can be driven with a sense of security. [Configuration] A headlight 201 for detecting a vehicle position
The central processing unit computes the illumination range 110 illuminated by. When the road surface condition is detected, the road illumination lamps 5a to 5c are made to have a light distribution characteristic directed to the front in the vehicle traveling direction to illuminate the illumination range 110 in a dry state. Beyond that range 112, 11
No. 4 illuminates with a downward or forward light distribution. Range 11
At 0, the contrast is not canceled, and at a distant place, the contrast effect of the road illumination lamp is effective. When the road surface is wet, the area 110 is illuminated by the light distribution in the front direction,
It complements the headlight light, which has almost no reflection from the road surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road lighting system for appropriately controlling nighttime lighting of a road on which a vehicle travels in accordance with the traveling environment of the vehicle.

[0002]

2. Description of the Related Art As one means for reducing accidents during night driving, a headlight is provided on the vehicle itself to illuminate the front, but the irradiation distance of the headlight is limited. , Road lighting by road lighting is used as an auxiliary.

Each of these illuminating means has its own characteristic. According to "Lighting of Roads and Passages" (Illumination Society of Japan, Society for Illumination Promotion, p.33, 1983), the headlight of a vehicle is shown in FIG. As shown in a), since the light is emitted substantially horizontally to the road surface, the road surface remains dark but the obstacle is illuminated brightly. On the other hand, since the road illumination lamp irradiates the road surface with light from above, as shown in (b) of the figure, even if the obstacle itself is dark, the road surface is illuminated brightly to raise the obstacle.

Since each of the lights allows the driver to drive with some margin, there are differences in the method, but when the driver recognizes an obstacle on the road, the obstacle itself and the background It is believed that it relies heavily on the contrast with.

[0005]

However, when both are lit, particularly in the range where the headlights of the vehicle are illuminated, it is clear that the obstacles are clearly identified by the bright illumination of both lights. Not always.

As described above, this is because, as described above, the illumination by the headlights of the vehicle has a bright obstacle but a dark background, and the road lighting has a bright background but a dark obstacle. Therefore, it is considered that the effects are canceled each other in the range in which the headlights of the automobile and the illumination of the road lighting overlap each other, and the effects are not sufficiently exerted.

As a countermeasure against this, as shown in FIG. 13, the irradiation direction of the road illumination lamp 405 is changed to the headlight 201 of the vehicle 200.
It is conceivable to unify the mechanism of contrast generation toward the traveling direction of the vehicle as well as the irradiation direction of. In this way, both the road illumination 405 and the headlight 201 have dark backgrounds and obstructions 13.
0 is brightly illuminated.

According to this, in fine weather, (a) of FIG.
It can be seen that a certain amount of reflection comes back from the road surface toward the driver as in the case of distant, but when the road surface becomes wet due to rainwater in rainy weather, as shown in (b) of the figure,
Light emitted forward in the traveling direction of the vehicle is specularly reflected and escapes, and almost never returns to the driver, and the road surface remains dark.

When the road surface is wet, the current road lighting is reflected on the road surface as shown in FIG. 15 (“Lighting of road / passage” (published by The Lighting Society of Japan, Lighting Promotion Society, p. 48, 1983)). Contrary to the above, it can be said that it is easier to recognize the existence of the obstacle itself by irradiating light from behind the obstacle 130 as shown in FIG. It will return to the problem.

Therefore, the present invention focuses on the above problems, and provides a road lighting device in which obstacles can be easily viewed in accordance with the weather and the condition of the road surface and the vehicle can be driven with a sense of security. The purpose is to

[0011]

Therefore, the present invention is based on FIG.
, A vehicle sensor 1 for detecting the position of a vehicle provided along the road, and a road surface condition detecting means 2 for detecting whether the road surface is in a dry state or a wet state,
The road illumination control means 3, the road illumination lamp 5, and the illumination lamp driving device 4 for lighting and driving the road illumination lamp 5 are provided, and the road illumination lamp 5 emits light forward along the road at least in the traveling direction. Having multiple light distribution characteristics including irradiation in the front direction,
The road illumination control means 3 obtains an illumination range in the longitudinal direction of the road illuminated by the headlights of the vehicle based on the information from the road surface condition detection means 2 and the vehicle sensor 1, and the illumination range illuminated by the headlights. When the road surface is in a dry state, it is illuminated by a road illumination light whose light distribution characteristic is in the forward direction, and when the road surface is in a wet state, it is illuminated by a road illumination light whose light distribution characteristic is in the front direction. A command is issued to the illumination lamp driving device 4.

[0012]

The vehicle sensor 1 detects the position of the vehicle along the road, and the road illumination control means 3 determines the illumination range illuminated by the vehicle headlight based on this information. The road lighting control means 3 further obtains the road surface state information from the road surface state detecting means 2, and when the road surface is in a dry state, the road lighting in the lighting range illuminated by the above headlight is irradiated forward in the traveling direction. Direction, the road lighting suitable for this is determined, and when the road surface is in a wet state, the road lighting in the lighting range illuminated by the headlights is performed in the irradiation direction to the front side of the vehicle. First, a road illumination lamp suitable for this is determined, and a lighting command including light distribution characteristics is issued to each illumination lamp driving device 4.

Thus, in the dry state, the illumination range illuminated by the headlights is overlapped with the road illumination having the same light distribution characteristic as the headlights, and the contrast effect is improved. In addition, when the vehicle is in a wet state, it is illuminated by a road illumination light that has a light distribution toward the front side of the vehicle. Due to this, the lack of visibility in headlight illumination where little reflection from the road surface is expected is reflected in the vehicle driver direction It is complemented by lighting by a lighting lamp.

[0014]

FIG. 2 shows an embodiment of the present invention. First, the configuration will be described. Road illumination lamps 5a, 5b, 5c, ... Having a light source 15 at the tip of the pole 10 are erected at predetermined intervals along the road 100, and a central processing unit 30 for controlling the entire system is provided. ing.

As shown in FIG. 3, the road illumination lights 5a, 5b, 5c, ... Are directed along the longitudinal direction of the road to a road surface in front of the vehicle 200, a road surface immediately below, and a road surface in the front direction. It has a light source 15 composed of unit light sources 15F, 15D, 15B which are independently controlled in three directions, and eaves 6, 6'are provided at the boundary of each light source. The eaves 6 has such a size that the light source 15F can be hidden even when the light source is viewed from directly below in the direction of arrow P.

Similarly, as fixed facilities, vehicle sensors 1a, 1b, ... Which detect the position of the vehicle 200 on the road 100.
And road surface condition detection means 2a for each of a plurality of road illumination lights,
, Are installed and connected to the central processing unit 30. The central processing unit 30 serves as road lighting control means.
On the basis of the information from the vehicle sensors 1a, 1b, ..., An illumination range 110 as a position in the longitudinal direction of the road illuminated by the headlight 201 mounted on the traveling vehicle 200 is calculated. At this time, an average fixed distance is used as the irradiation distance of the headlight 201. Then, based on the calculation result and the information from the road surface condition detecting means 2a, 2b, ..., Lighting is performed for the lighting lamp driving devices 4a, 4b, 4c ,. And a light distribution command is issued, and the light source 15 attached to the pole 10 illuminates with the instructed light distribution.

As shown in FIG. 4, each of the road surface condition detecting means 2a, 2b, ... Includes a light emitting device 22 for emitting a laser beam 26 toward the road surface 101 and a light receiving device 24 for receiving the reflected light 28. From the change of the reflected light intensity, the road surface condition of whether the road surface 101 is dry or wet is determined.

Illumination of the road in this embodiment is performed by the flow of FIG. In step 301, the vehicle sensor 1a,
When the traveling vehicle 200 is detected by any one of the vehicle sensors 1b, ...
At 0, the vehicle position along the road 100 is calculated in step 302. Step 303 based on this vehicle position
Then, a point on the road from the front end of the vehicle 200 is illuminated by the headlight 201 of the vehicle, that is, an illumination range 110 by the headlight is calculated. In step 304, information from the road surface condition detecting means 2a, 2b, ... Is input.

In step 305, a road illumination light is determined according to the road surface condition for illuminating the illumination range 110 obtained in step 303, and then in step 306, a predetermined range following the illumination range 110 and further away. A road illumination lamp that illuminates a predetermined distance portion is determined.

That is, when the road surface is dry, as shown in FIG. 6, the road illumination lights 5a, 5b and the road illumination lights 5a, 5b which can illuminate the illumination range 110 with the light distribution characteristic in the same direction as the traveling direction of the vehicle 200. 5c is determined, and subsequently, the road illumination lights 5f, 5g, and 5 that cover the predetermined range 112 following the lighting range 110 when the irradiation direction is directed substantially directly below.
While h is determined, the road illumination lights 5k and 5l that cover the predetermined distance portion 114 farther than these when the irradiation direction is the front direction are determined.

When the road surface is in a wet state, as shown in FIG. 7, a road illumination lamp 5d capable of illuminating the illumination range 110 with a light distribution characteristic in which the irradiation direction is the front side of the vehicle,
5e and 5f are determined, and subsequently, a predetermined range 116 that follows the lighting range 110 and a predetermined range 118 that follows the lighting range 110 can be illuminated with a light distribution characteristic in which the irradiation direction is similarly set to the vehicle side front direction. 5g, 5h, 5i and 5
j is determined.

Thereafter, in step 307, a lighting command including the light distribution characteristic is sent to the above-determined illumination lamp driving device of each road illumination lamp. As a result, at the time of road surface drying, road illumination is performed on the portion illuminated by the headlight 201 in the same direction as the traveling direction of the vehicle, and a predetermined range following this is illuminated from above to substantially immediately below. The range farther than these is illuminated toward the vehicle toward the front. Further, when the road surface is wet, the area is illuminated by a road illumination light including the area illuminated by the headlight 201 toward the vehicle.

After lighting, it is checked in step 308 whether or not the vehicle 200 is detected by the vehicle sensor. If it is detected, the flow from step 302 onward is repeated, and if the vehicle position changes, the vehicle is lit accordingly. Road lighting and its light distribution characteristics are changed. Even if the vehicle 200 moves out of the detection range of the vehicle sensor and is no longer detected, in step 309 the lighting is continued for a certain period of time sufficient to reach the detection range of the adjacent vehicle sensor.

As a result, when the road surface is dry, the contrast is not canceled in the area illuminated by the headlight, and the contrast effect of the road illumination lamp is effectively used in the distant area where the illumination of the headlight does not reach. Thus, the visibility of the obstacle is secured. At this time, because the light source is provided with an eaves,
There is no fear that the leaked light from the light source 15 will enter the eyes of the driver and make the driver uncomfortable each time the light passes through the road lighting lights 5a, 5b, and 5c. Also, at this time, the road illumination lights 5d and 5e
The light distribution may be in the traveling direction of the vehicle or directly below, but if it is turned off, it also contributes to power saving.

Further, when the road is a two-way road,
When an oncoming vehicle approaches, the road illumination light between the vehicles is switched to direct illumination so as not to dazzle the driver.

When the road surface is in a wet state due to rain or the like, it is illuminated by a road illumination light whose light distribution is directed toward the front side of the vehicle including the area illuminated by the headlight, which causes reflection from the road surface. The lack of visibility in headlight lighting, which is hardly expected, is complemented by the illumination by road lighting that reflects toward the driver of the vehicle.
In this case, in order to prevent the strong light of the road lighting from directly entering the eyes of the driver, the road lighting 5a, 5b close to the vehicle,
5c is turned off or dimmed.

Note that the illumination range of the road illumination light that illuminates forward in the traveling direction of the vehicle is wider than that of the road illumination light that illuminates directly below the road surface because the illumination direction is inclined. As shown in FIG. 8, when the road surface is dry, the road lighting lights 5a, 5c are thinned out, for example, as shown in FIG. The lighting interval can be extended. Furthermore, the road illumination lights 5j and 5l farther than the road illumination lights that illuminate directly below may be turned on with an amount of light such that the far road alignment can be clearly shown. Similarly, when wet, as shown in FIG. 9, the area illuminated by the road illumination lamp can be thinned out to the extent that it is not interrupted. This can further save energy.

The control of the road illumination light by the central processing unit 30 is not limited to this. If the vehicle speed is detected together with the vehicle position detection by the vehicle sensor, the vehicle 200 goes out of the detection range of the vehicle sensors 1a, 1b, .... In the meantime, the vehicle position is estimated to accurately determine the illumination range 110 by the headlights, so that the installation interval of the vehicle sensors 1a, 1b, ... Can be lengthened, and smooth lighting control can be realized without incurring equipment costs. Vehicle speed detection methods include vehicle sensors 1a, 1b,
The method of detecting the instantaneous speed with ..., the vehicle sensors 1a, 1
It can be calculated by the central processing unit 30 from the time when the distance between b, ... Is moved.

As the vehicle speed increases, the quantity of light to be turned on may be increased. For this reason, the quantity of light of the light source 15 can be changed in a plurality of steps, or the unit light source 15F in three directions can be used.
, 15D and 15B can be turned on by combining a plurality of directions instead of turning on only one of them at a time. Further, when the vehicle speed is low, it is possible to turn on only the road illumination lamp that illuminates the illumination range 110 of the headlight and not turn on the vehicles farther than that. That is, in the case of FIG.
a, 5b and 5c only, and in FIG.
It can be d, 5e and 5f only.

Further, as shown in FIG. 10, the light source of the road illumination light is a light source 15 'composed of two unit light sources 15B' and 15F 'which are directed in the front direction and the vehicle traveling direction along the longitudinal direction of the road. Light control can also be simplified.
Also in this case, the eaves 6 "may be provided so that the light source radiating forward in the traveling direction of the vehicle is hidden from the driver's visual field P ', thereby limiting the leaked light.

FIG. 11 is a block diagram showing the structure of another embodiment. Instead of the vehicle sensor, each road illumination light 5a, 5
The central processing unit 30 ′ includes a brightness sensor 11a, 11b, 11c, ... For detecting the brightness distribution of the road surface, which is installed for each of b, 5c ,.
Is calculated based on the vehicle position, instead of the brightness sensor 11
From the luminance detected by a, 11b, 11c, ..., Which luminance detection point is within the range illuminated by the headlight 201 of the vehicle is determined.

According to this, there is an advantage that even when the illumination range of the headlight differs depending on the vehicle, or when the illumination range of the headlight is switched, it is possible to more finely deal with the situation.

[0033]

As described above, according to the present invention, the distribution of the road lighting is controlled according to the condition of the road surface, so that the respective effects of the road lighting and the headlight of the vehicle can be sufficiently exhibited. Therefore, night visibility can be secured regardless of the weather, and safer night driving can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the invention.

FIG. 2 is a diagram showing an embodiment of the invention.

FIG. 3 is a diagram showing a light source of a road illumination lamp.

FIG. 4 is a diagram showing an example of road surface condition detection means.

FIG. 5 is a flowchart showing the operation of the embodiment.

FIG. 6 is a diagram illustrating an illumination mode in a dry road surface state.

FIG. 7 is a diagram illustrating an illumination mode in a road surface wet state.

FIG. 8 is a diagram illustrating another illumination mode in a dry road surface state.

FIG. 9 is a diagram illustrating another illumination mode in a road surface wet state.

FIG. 10 is a diagram showing another example of a light source of a road illumination lamp.

FIG. 11 is a block diagram showing the configuration of another embodiment.

FIG. 12 is a diagram showing how an obstacle is seen depending on the type of illumination.

FIG. 13 is an explanatory diagram of an example of illumination.

FIG. 14 is a diagram illustrating reflection of illumination light of a headlight.

FIG. 15 is a diagram showing how the road lighting looks when the road surface is wet.

FIG. 16 is an explanatory diagram of another example of illumination.

[Explanation of symbols]

 1, 1a, 1b Vehicle sensor 2, 2a, 2b Road surface condition detecting means 3 Road lighting control means 4, 4a, 4b, 4c, ... Lighting lamp driving device 5, 5a, 5b, 5c, ... Road lighting 6, 6 ' , 6 "eaves 10 pole 11a, 11b, 11c brightness sensor 15, 15 'light source 22 light emitting device 24 light receiving device 26 laser light 28 reflected light 30, 30' central processing unit 100 road 101 road surface 110 irradiation range 130 obstacle 200 vehicle 201 Headlight 405 road lighting

Front Page Continuation (72) Inventor Masanori Saito 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (1)

[Claims] 1. A vehicle sensor for detecting the position of a vehicle provided along a road, a road surface condition detecting means for detecting whether the road surface is in a dry state or a wet state, a road lighting control means, and a road. An illumination lamp and an illumination lamp drive device for driving and driving the road illumination lamp, wherein the road illumination light has a plurality of light distribution characteristics including irradiation in the forward direction and in the front direction along the road. The road illumination control means obtains an illumination range in the longitudinal direction of the road illuminated by the vehicle headlights based on the information from the road surface condition detection means and the vehicle sensor, and the illumination illuminated by the headlights. When the road surface is dry, the range is illuminated by a road illumination light with the light distribution characteristic forward, and when the road surface is wet, the area is illuminated with a road illumination light with the light distribution characteristic toward the front. You A road illumination device, characterized in that a command is issued to the illumination lamp drive device.