JPH0466343A - Headlamp device for vehicle - Google Patents

Abstract

PURPOSE:To produce a traveling environment in which a driver can distinguish visual information all the time by judging visibility of the visual information in front of a car on the basis of brightness distribution in a front visual field and brightness distribution state of a road surface due to light distribution from a headlamp of an own car, and also controlling a light distribution changing means according to the result of the judgment. CONSTITUTION:In a headlamp device of a car composed of a headlamp CL1, whose light distribution can be changed, and light distribution changing means CL2, which changes the light distribution of the headlamp CL1, there are provided a detecting means CL3 for detecting brightness distribution in a visual field in the proceeding direction, and a judging means CL4 for judging brightness distribution state due to the light distribution of the headlamp of a driver's own car. Output from these devices is input to a visibility judging means CL5. The visibility of the visual information in the visual field in front of the car is judged on the basis of the brightness distribution and the brightness distribution state. Then, the light distribution changing means CL2 is controlled by means of a control means CL6 according to the result of the judgment. Consequently, when th visibility of the visual information of obstructions and the like in the visual field ahead of the car becomes poor owing to the light from the headlamp of the driver's own car, the light distribution of the headlamp is changed for producing the traveling environment in which the driver can distinguish the visual information easily.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention detects the brightness distribution within the forward visual field and controls the light distribution of the own military headlights based on the detection. The present invention relates to a vehicle headlamp device.

(Prior Art) In general, automobile headlamp systems use two-way high beams (driving beams) that are used when driving on roads with no preceding or oncoming vehicles, and two-way high beams (driving beams) that are used when driving on roads with no preceding or oncoming vehicles, or in urban areas. A downward-facing low beam used when driving (
Both beams can be switched manually or automatically.

As a conventional headlamp device of this type, for example, Japanese Patent Application Laid-open No. 1983
There is one described in Japanese Patent No.-105245.

This headlight device has means for detecting light emitted from the taillights of a preceding vehicle and the headlights of an oncoming vehicle, and automatically switches to low beam when light from at least one of the lamps is detected. This is designed to avoid dazzling oncoming vehicles or those ahead of you.

(Problem to be solved by the invention) With such a headlamp device, when there is no oncoming vehicle, the driver cannot visually see the road surface or obstacles illuminated by the light from his own army's headlights. Run. In general, the reflection coefficient between the road surface and the obstacle is smaller, so the brightness of the obstacle becomes higher and it appears as an inverted silhouette.

However, when an oncoming vehicle is behind an obstacle, the brightness of the road surface increases due to the light from the oncoming vehicle's lamps, but on the other hand, the brightness does not change because the obstacle is illuminated from behind. As a result, obstacles appear as silhouettes.

Therefore, depending on the relative position of the oncoming vehicle, the obstacle, and the driver's own vehicle, the difference between the brightness of the obstacle illuminated by the vehicle's own vehicle's headlights and the road surface brightness illuminated by the oncoming vehicle's lamps may become small, causing the driver to notice the obstacle. There was a so-called evaporation phenomenon in which people overlooked things.

Therefore, this invention changes the light distribution of the own vehicle's headlights when the visibility of visual information such as obstacles in the front field of view is deteriorated due to the light of the own vehicle's headlights. An object of the present invention is to provide a vehicle headlight device that can create a driving environment that is easy for a driver to see.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a headlight CL1 that can change the light distribution as shown in FIG.
In a vehicle headlamp device comprising means CL2 for changing the light distribution of the vehicle, means CL3 for detecting the brightness distribution within the field of view of the vehicle, and determining the brightness distribution situation based on the light distribution of the own vehicle's headlights. means CL4, and means C for determining the visibility of visual information within the forward visual field from the luminance distribution and the luminance distribution situation;
L5, and a control means CL6 that controls the light distribution changing means CL2 according to the output of the visibility determining means CL5.

(Function) According to the above configuration, the visibility of the visual information ahead is controlled based on the brightness distribution in the forward visual field detected by the brightness distribution detection means CL3 and the brightness distribution situation on the road surface according to the light distribution of the own army headlight CL1. This visibility determining means C is determined by the means CL5.
The control means CL6 changes the light distribution changing means CL according to the output of L5.
Control 2.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a block diagram of a vehicle headlamp device according to an embodiment of the present invention, and FIG. 3 is a flowchart based on the block diagram of FIG. 2.

As shown in FIG. 2, the vehicle headlamp device includes a brightness detection sensor 1 as a brightness distribution detection means CL3 that detects brightness within the front field of view, and a vehicle speed sensor 3 that detects the own vehicle speed Vt. . The brightness detection sensor 1 images the front field of view using, for example, a TV camera, and determines the brightness distribution of the road surface from the gray level of the image signal. The vehicle speed sensor 3 detects the vehicle speed by receiving a signal from a speedometer, for example.

The brightness detection sensor 1 and the vehicle speed sensor 3 are connected to a microcomputer 5 constituting a visual recognition determination means CL5.

The microcomputer 5 detects the brightness distribution situation in the forward field of view detected by the brightness detection sensor 1 and the own army headlights 7.
The visibility within the forward field of vision is determined from the brightness distribution of the road surface ahead due to the light distribution of (CLl), and the control amount of the light distribution of the own vehicle headlight 7 is calculated.

The microcomputer 5 is connected to a drive circuit 9 which is a light distribution changing means CL2 that changes the light distribution of the headlamp 7 based on the determination result of the microcomputer 5.

Next, the operation of the above embodiment will be explained based on the flowchart of FIG.

First, in step S1, an image signal of the forward field of view from the brightness detection sensor is input as the brightness distribution of the road surface. At the same time, in step S2, the vehicle speed signal Vt from the vehicle speed sensor 3 is input. Next, in step s3, it is determined whether the vehicle speed Vt is 10 km/h or less. If the vehicle speed Vt is 10 km/h or less, it is determined that the vehicle is driving slowly and the process returns to step s1. If the vehicle speed Vt is 10 km/h or more, it is determined that the vehicle is not driving slowly, and the process moves to step s4, where FLAG is set to 1.
It is determined whether or not. If it is FLAG-0, the process moves to step s5 as the first calculation, the light intensity distribution of the own army headlight 7 is input, and in step s6 it is set to FLAG-1. When FLAG=1 in step S4, it is controlled that the luminous intensity distribution has already been input, and the process moves to step S7.

In step S7, the luminance distribution of the road surface ahead due to the irradiation of the self-weighted headlight 7 is calculated from the luminous intensity distribution of the own army headlight 7. Then, in step S8, it is determined whether there is an oncoming vehicle. If there is no oncoming vehicle, return to step S1,
If there is an oncoming vehicle, the process moves to step S9, where the brightness of the front field of view is compared with the brightness distribution calculated in step s7, and the brightness Lt of the obstacle ahead is calculated. Subsequently, in step S10, the surrounding brightness Lb of the obstacle is calculated.

Next, in step S11, the brightness difference ΔLi between the obstacle brightness Lt and the surrounding brightness Lb is calculated as ΔLi−Lb−Lt.

In step 512, the brightness difference ΔLi is compared with a predetermined brightness setting value ΔLo. If the brightness difference is △L1 or the set value △Lo, it is determined that the obstacle is visible12
and return to step S]. If the brightness difference △L1 is smaller than the predetermined set value △Lo, the process moves to step 513, and the difference △Ln between the brightness difference △Li and the set value △Lo is △L
n−△L.

~ΔLi.

Next, in step S14, whether the brightness difference ΔLi or the set value ΔLo
Calculate the control amount of the headlight light distribution so that it becomes larger than 1
7. The output from the drive circuit 9 (- changes the light distribution of the headlight 7) based on this control amount (step 515).

Therefore, if the visibility of the own vehicle's headlights 7 is deteriorated, the evaporation phenomenon can be prevented by distributing the own vehicle's headlights 7 so as to reduce the irradiation on obstacles.

The light distribution of the bright lights 7 in front of the vehicle may be changed by switching between high beam and low beam.
By attaching a liquid crystal filter divided into a matrix to the reflector like No. 6, and controlling this filter, more fine control can be achieved.

FIG. 4 shows an example of a detailed flowchart of the road surface brightness calculation method in step S7 of FIG.

In this embodiment, it is determined whether the road surface on which the vehicle is traveling is wet or dry, and road surface brightness is calculated using a reflection coefficient depending on each road surface.

That is, first, in step 5201, the luminous intensity distribution of the self-weight headlamp 7 is input, and then, in step 5202, it is determined whether or not the road surface ahead is wet. If it is determined that the road surface is wet, the process moves to step 8203 (7, the reflection coefficient of the road surface when it is wet is read. If it is determined that the road surface is not wet, the process moves to step 204, and if the road surface is dry, the process moves to step 8203. Then, in step 5205, the road surface brightness of the road ahead is calculated from the luminous intensity distribution of the headlights and the road surface reflection coefficient.

FIG. 5 shows another embodiment of a detailed flowchart of the road surface brightness calculation method. Steps similar to those in FIG. 4 are given the same reference numerals, and redundant explanation will be omitted.

In this embodiment, when the reflection coefficient differs depending on the road surface on which the vehicle is traveling, for example, asphalt road surface, concrete road surface, etc., the brightness of the representative point) is measured several times, and this result is stored as the basic brightness. This is to correct the reflection coefficient of the road surface on which the road surface is located, and step 5206 and S 2 (17) are added to the flowchart of FIG.

That is, in step 5206, the basic luminance Lk is input,
The stored reflection coefficient is corrected using this basic luminance Lk (step S 2 (17)).

According to this embodiment, it is possible to calculate the road surface luminance more accurately by 1F.

6 to 8 show other embodiments of the present invention.

In this embodiment, as shown in FIG. 6, an obstacle detection feature is added to the previously described embodiment. Second
Elements that are the same as those in the figures are given the same reference numerals and their explanations will be omitted.

The obstacle detection sensor 11 is configured, for example, by a laser attached to both front parts of Φ, and determines the position of the obstacle 13 based on the time it takes for the transmitted laser to be reflected by the obstacle 13 and received (7). (See Figure 7).

FIG. 8 shows a flowchart of this embodiment. Step 1 is similar to the step in Figure 3. The same reference numerals are used to omit duplicate explanations.

That is, in step S16, the detection signal from the obstacle detection sensor 11 is input, and this detection signal ? Based on this, the brightness Lt of the obstacle ahead is calculated (step 510).

Therefore, the brightness Lt of the obstacle can be calculated more accurately. In the above-mentioned embodiments, the beams are switched as a means of changing the light distribution, but the invention is not limited to this, and it is also possible to make a part of the reflector movable or to replace the lens.

[Effects of the Invention] As is clear from the above description, according to the configuration of the present invention, the visibility of visual information existing within the forward field of view is improved regardless of the presence or absence of oncoming vehicles, etc., so that the driver can avoid obstacles, etc. It is possible to create a driving situation where it is easy to see the vehicle.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the present invention, Fig. 2 is a block diagram of a vehicle headlamp according to an embodiment of the invention, Fig. 3 is a flowchart based on the block diagram of Fig. 2, and Fig. 4 is a block diagram of a vehicle headlamp according to an embodiment of the invention. 3 is a detailed flowchart of step S7 according to one embodiment, FIG. 5 is a flowchart explaining step S7 according to another embodiment, and FIG. 6 is a detailed flowchart of a vehicle headlamp device according to another embodiment of the present invention. FIG. 7 is a block diagram showing the operation of the obstacle detection sensor, and FIG. 8 is a flowchart based on the block diagram of FIG. 6. CLI...Headlight Cl3...Light distribution changing means Cl3...Brightness distribution detection means Cl3...Brightness distribution situation judgment means CL5...Visibility judgment means Cl6...Control means agent Patent attorney Hidekazu Miyoshi 4th IA 11 (Laser)

Claims (1)

[Claims] A vehicle headlamp device comprising a headlamp whose light distribution can be changed and a means for changing the light distribution of the headlamp includes a means for detecting a luminance distribution within the field of view of the vehicle; means for determining a brightness distribution situation based on the light distribution of a headlamp; a means for determining the visibility of visual information within the forward visual field from the brightness distribution and the brightness distribution situation; A vehicle headlamp device comprising a control means for controlling a light distribution changing means.