JPH10188602A - Headlamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To illuminate a portion immediately in front of a vehicle for the detection of deviation from a course, without using parts such as a reflector, a prism or a reflecting plate, in a headlamp in which a discharge lamp, a reflector, which is constituted of a paraboloidal part provided with the discharge lamp on its focus and reflects the backward illuminating light of the discharge lamp in parallel light and a cylindrical part coupled to the outside of the paraboloidal part, and a light blocking plate provided on the front surface of the discharge lamp to block the direct light of the discharge lamp and the part of the parallel light forming glare, are enclosed in a lamp main body. SOLUTION: A light diffusing part 45 is provided at the cylindrical part 42b of a reflector 42, and an opening 44 in a light blocking plate 43 on the front surface of a discharge lamp is provided in a position where a straight line connecting the light diffusing part 45 to the focus F of the paraboloidal part 42a of a reflector in which the discharge lamp 41 is placed crosses the light blocking plate 43, so that light emitted from the discharge lamp 41 and reflected by the light diffusing part 45 via the opening 44 illuminates a visual field on a road for detection by a line detection means installed on top of the front end of a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a headlamp, and more particularly to a headlamp including a high-intensity discharge lamp (HID) as a light source.

[0001]

2. Description of the Related Art In recent years, high-luminance headlamps including a high-intensity discharge lamp as a light source have been developed and are being adopted for trucks and the like.

[0002] Such a high-intensity discharge lamp has a higher light flux and a higher color temperature than a conventional halogen lamp, so that the visibility of the driver when the vehicle is running at night is increased, the burden on the driver is reduced, and the safety is reduced. Contribute to the improvement of

FIG. 3 is a plan view of such a conventional headlamp. In the figure, reference numeral 1 denotes the entire headlamp. The headlamp 1 is covered with a lamp body 2 and a lens 3. With two headlamps,
That is, the passing (downward) beam headlamp 4 and the traveling (upward) beam headlamp 5 are provided as shown.

The headlamp 4 for passing (downward) beams is a discharge lamp 41 and a reflector 4 mounted on the back of the discharge lamp 41 and reflecting the light emitted from the discharge lamp 41.
2 and a light-shielding plate 43 mounted on the front of the discharge lamp 41 to shield direct light and light reflected from the reflector 42.

A headlamp 5 for a traveling (upward) beam includes a halogen lamp 51 and the halogen lamp 51.
And a reflector 52 which is mounted on the back of the projector and reflects the irradiation light of the halogen lamp 51.

FIG. 4 is a side view of the low-beam headlamp 4 in the headlamp 1 shown in FIG. 3. The light-shielding plate 43 has a notch 43a and a lower part 43b. Is screwed with a support 43c, for example, as shown in FIG.

When a paraboloid of revolution is used for the reflector 42, the light emitted from the headlamp 1 is
The incidence of light on a cylindrical portion (standing wall) 42 b other than the parabolic surface portion 42 a, which is an effective surface of the reflector 42, is blocked by the light shielding plate 43.

Further, since the discharge lamp 41 is disposed near the focal point F of the parabolic surface portion 42a of the reflector 42, the irradiation light indicated by a dashed line from the focal point F and the notch 43a of the light shielding plate 43 Go through it horizontally as shown,
The driver and pedestrian of an oncoming vehicle or a preceding vehicle are not dazzled or glare.

On the other hand, in a truck or the like, the driver's viewpoint is high, and the range of visibility is not only in the normal lamp irradiation range but also in the vicinity of the left and right of the vehicle and the position immediately before the vehicle. Irradiation light is required.

Particularly, in a lane departure warning device provided with a line camera (line sensor) above the front end of the vehicle, the sensor field of view of the line camera is set immediately before the vehicle in order to accurately detect the deviation of the vehicle from the lane. In order to accurately perform lane detection at night, irradiation light near the vehicle or up to a position immediately before the vehicle is required.

This will be described in detail with reference to FIG.
Vehicle 1 equipped with lane departure warning device as shown in (2)
The headlamp 0 is usually designed and mounted for the purpose of securing a nighttime visual field a by the driver's naked eye point EP, and the irradiation range b (shaded area) of the headlamp 1 is as shown in FIG. It is limited to the field of view a. Therefore, the field of view c of the line camera 11 necessary for accurately and accurately detecting the deviation of the vehicle 10 from the lane cannot be set to a position immediately before (just before) the front of the vehicle.

[0012] Therefore, during night driving, the warning process is performed only in the range of a few meters from the front end of the vehicle to be subjected to the lane detection by relying only on accidentally leaking light, so that the lane detection at night can be accurately performed. And the function of the lane departure warning device cannot be achieved.

In order to solve this problem, Japanese Patent Application Laid-Open No. 6-284334 and Japanese Patent Application No. 8-27649, which are improved versions thereof (both by the present applicant), dispose a prism or a reflector on the lens glass surface. A technique has been proposed in which a part of the irradiation light from the headlamp is leaked to the vicinity of the vehicle by combining such separate parts.

Thus, as shown in FIGS. 6A and 6B, the headlamp 1 of the vehicle 10 generates a leakage beam D from the irradiation beam B, thereby
The road surface portion for the visual field c to be photographed by the line camera 11 immediately before is illuminated, an image signal is output, and a lane on the road is extracted from the image signal.

When the distance between the lane and the vehicle is in a dangerous state below a certain position, an alarm is issued assuming that the alarm operation condition is satisfied unless the direction instruction operation is performed.

[0016]

However, as described above, when a part of the irradiation beam from the discharge lamp light source of the headlamp is leaked by the reflecting mirror, the prism or the reflection plate on the rear surface, the irradiation beam itself from the light source is generated. There is unevenness, and the reflecting mirror also has unevenness on the surface.

For this reason, in a portion of the road surface where the illuminance is high, even if the lane does not exist, reflection occurs at the same level or more as the lane, and as shown in FIG. In some cases, a small luminance portion 22 appears.

Especially at night or the like, since the detection gain is increased while keeping the threshold for lane detection constant, when the signal level of the lane 21 is low due to blurring of the lane 21 or the like, the other parts 22 are moved to the lane. Erroneously as a lane departure warning device.

Further, since another part for leaking a part of the irradiation beam from the light source of the headlamp through the rear-side reflecting mirror and the prism or the reflecting plate is combined, the lens needs to be processed, and the manufacturing is difficult. is there.

Further, since another component protrudes outside the lens glass surface, there is a problem that the component is easily hooked and the durability is uneasy.

Accordingly, the present invention provides a discharge lamp, a parabolic surface portion provided with the discharge lamp at a focal point thereof, and a parabolic surface portion for reflecting irradiation light in the back direction of the discharge lamp as parallel light, and a cylindrical portion coupled to the outside thereof. And a light shielding plate provided on the front surface of the discharge lamp and shielding a part of the discharge lamp that becomes a direct light and a glare light of the parallel light. An object of the present invention is to irradiate a portion immediately before a vehicle for detecting a lane departure without using another component such as a mirror, a prism, or a reflector.

[0022]

In order to achieve the above object, a headlamp according to the present invention is provided with a light diffusing portion provided in a cylindrical portion of a reflector, and the light diffusing portion and the focal point of a parabolic surface of the reflector are focused. An opening of the light-shielding plate is provided at a position where the straight line that connects and the light-shielding plate intersects, whereby light reflected by the light diffusing portion via the opening from the discharge lamp provided at the focal point,
The present invention is characterized in that a detection field of view on a road surface of a lane detecting means installed at an upper part of a front end of the vehicle is irradiated.

That is, the irradiation light from the back of the discharge lamp is reflected by the parabolic surface of the reflector and emitted from the lamp body as parallel light as in the conventional case. However, in the present invention, since the light shielding plate is provided with the opening, it is provided. Irradiation light passing through the opening is reflected by a light diffusion portion (preferably a portion having an irregular uneven diffusion curved surface) provided in a cylindrical portion which is connected to the outside of the paraboloid portion of the reflector. Illuminate the road surface.

In this case, the position of the discharge lamp, that is, the relative positional relationship between the focal point of the parabolic surface portion of the reflector, the opening, and the light diffusing portion is such that the light reflected by the light diffusing portion is at the front end of the vehicle. The lane detecting means is set so as to irradiate the detection visual field on the road surface of the lane detecting means installed at the upper part. Since the detection can be performed, an accurate lane departure warning can be issued.

When the upper surface of the light-shielding plate is notched as in the present invention, instead of providing an opening in the light-shielding plate, a large amount of light from the discharge lamp is irradiated onto the upper part of the light-shielding plate. It is difficult to know what kind of diffuse reflection will occur, and it will be reflected where it should not be irradiated,
There is a possibility that the glare light becomes dazzling.

According to the present invention, an opening is provided in the light-shielding plate so as to irradiate only a minimum required road surface portion (a detection visual field portion on the road surface of the lane detecting means) for performing a lane departure warning, thereby transmitting light. Unnecessary irradiation light is removed.

The light diffusing portion cannot illuminate the detection field on the road surface of the lane detecting means depending on the length of the cylindrical portion. It is sufficient to provide a light diffusing unit in the light emitting device.

[0028]

FIG. 1 is a side view of an embodiment of a headlamp according to the present invention. In this embodiment, the headlamp is slightly shifted (downward) as compared with the conventional example shown in FIG.
An opening 44 as shown in FIG. 2B is provided on the upper surface of the light shielding plate 43 of the beam headlamp 4, and further, an upper portion of a cylindrical portion (standing wall) 42 b coupled to a parabolic surface 42 a of the reflector 42. A light diffusing unit 45 is provided which is extended and attached to the light emitting device.

That is, the light emitted from the discharge lamp 41 whose light source center is disposed at the focal point F of the paraboloid portion 42a is indicated by an arrow L
The light passes through the opening 44 and is reflected by the diffusion curved surface of the light diffusion portion 45 attached to the cylindrical portion 42b of the reflector 42 as shown by.

The reflected light L diffused by the light diffusion section 45 passes through the lens 3 and reaches the road surface position in the detection visual field range c of the line camera 11 shown in FIG.

If the light is not diffused by the light diffusing unit 45 as described above, unevenness will appear on the road surface due to the refraction due to the boundaries between the respective minute prisms of the lens 3 and the steps thereof, and the line camera 11
May cause false detection.

FIG. 2 shows an embodiment of the light diffusing section 45 used in the headlamp according to the present invention shown in FIG. 1. In the embodiment shown in FIG. Particle 3
2, a white or silver coating 33 for fixing the particles is applied on the fine particles 32. The base material 31
Is sufficient if it has only mechanical strength.

Further, in the embodiment shown in FIG.
A coating 33 is applied thereon, and white or silver fine particles 32 are provided on the coating 33 so that the fine particles 3
2 is fixed to the coating 33. In the embodiment shown in FIG. 3C, the reflection surface of the base material 31 is diffused with irregularities.

In any case, the discharge lamp is characterized by not having a high temperature and having a small infrared component as compared with a general halogen bulb (light source). Preferably, material 31, particles 32, and coating 33 are used.

Any member may be used as long as it has irregularities on the surface and irregularly reflects incident light, but a member having a so-called uniform diffusion surface is preferable.

The opening area of the opening 44 is such that the light L from the discharge lamp 41 can reach the leak beam range D shown in FIG. 6, that is, the range in which the lane detection visual field c of the line camera 11 can be covered. It may be set as follows.

This can be designed by the optical path tracing analysis from the light source of the discharge lamp 41 together with the specification (design) of the diffusion curved surface of the light diffusion section 45 shown in FIG.

In the above embodiment, the light diffusing portion 45 is attached to the cylindrical portion 42b of the reflector 42 so as to be extended. However, depending on the length of the cylindrical portion 42b, the detection field of view on the road surface of the line camera 11 is different. In this case, the light diffusing portion 45 may be provided at a predetermined position of the cylindrical portion 42b or attached thereto, and need not be newly provided.

[0039]

As described above, according to the headlamp of the present invention, the light diffusing portion is provided on the cylindrical portion of the reflector, and the light diffusing portion and the focal point of the parabolic surface portion of the reflector on which the discharge lamp is disposed. An opening portion of the light-shielding plate is provided at a position where the straight line connecting the light-shielding plate on the front of the discharge lamp intersects, whereby light reflected by the light diffusing portion from the discharge lamp via the opening portion,
Since the detection field of view on the road surface of the lane detection means installed at the upper part of the front end of the vehicle is illuminated, an opening is formed in a part of the light shielding plate without coupling other components such as a prism and a reflector to the headlamp. The light from the discharge lamp light source can be almost uniformly applied to the detection range of the lane detecting means only by providing the lane detecting means, and the lane departure warning at the time of running at night can be accurately executed.

Further, by providing the light shielding plate with the opening, it is possible to irradiate the detection range of the lane detecting means with light from the discharge lamp light source without increasing glare light to oncoming vehicles and pedestrians.

[Brief description of the drawings]

FIG. 1 is a side view of a headlamp for a low-pass (downward) beam in a headlamp according to the present invention.

FIG. 2 is a side sectional view schematically showing an embodiment of a light diffusing unit used in a headlamp according to the present invention.

FIG. 3 is a plan view of a conventional headlamp.

FIG. 4 is a side view of a low-beam headlamp in a conventional headlamp.

FIG. 5 is a diagram showing a range in which visibility of a truck at night must be improved.

FIG. 6 is a diagram for explaining an illumination operation by a conventional headlamp.

FIG. 7 is a graph for explaining a problem in a conventional headlamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head lamp 2 Lamp main body 3 Lens 4 Head lamp for passing (downward) beam 41 Discharge lamp 42 Reflector 42a Parabolic surface part 42b Cylindrical part (standing wall) 43 Light shielding plate 44 Opening part 45 Light diffusing part The corresponding parts are shown.

Claims (2)

[Claims] 1. A discharge lamp comprising: a discharge lamp; a discharge lamp provided at a focal point of the discharge lamp; a parabolic surface portion for reflecting irradiation light in a rear direction of the discharge lamp as parallel light; and a cylindrical portion coupled to the outside thereof. A reflector provided on a front surface of the discharge lamp and a light-shielding plate for shielding a portion of the discharge lamp which becomes glare light of the direct light and the parallel light. A light-diffusing portion is provided and an opening of the light-shielding plate is provided at a position where the straight line connecting the light-diffusing portion and the focal point and the light-shielding plate intersect, whereby the discharge lamp passes through the opening through the opening. A headlamp characterized in that light reflected by a light diffusing portion irradiates a detection field of view on a road surface of a lane detecting means installed at an upper part of a front end of a vehicle. 2. The headlamp according to claim 1, wherein the light diffusing portion is provided in a shape protruding from the cylindrical portion.