Illumination – Supported by vehicle structure – Projection-type headlamp
Reexamination Certificate
2000-09-27
2001-10-30
Husar, Stephen (Department: 2875)
Illumination
Supported by vehicle structure
Projection-type headlamp
C362S465000, C362S514000, C362S523000
Reexamination Certificate
active
06309094
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a projection headlight for a vehicle, particularly a motor vehicle, including a reflector, a light source mounted in the reflector peak region, at least one stop or mask arranged in front of the reflector and a projection lens arranged in front of the stop or mask. It also relates to an illumination device for a motor vehicle including at least two of these projection headlights, particularly on opposite sides of the vehicle.
2. Prior Art
Because of the only limited available light intensities that they produce headlights for motor vehicles are designed to illuminate a straight section of road of a customary width. The comparatively large light intensities required for visibility purposes are concentrated on the right side of the street at a distance of about 50 m in front of the motor vehicle. During travel of the vehicle around a curve it is appropriate to laterally shift the direction of propagation of the maximum light intensities.
A lighting device for a motor vehicle is described in DT 1 580 740 with rotatably mounted headlights, which provides curve illumination of the curved path of a vehicle travelling around a curve. The entire headlight is rotatable about an at least approximately vertical axis in the frame of the vehicle in this lighting device. The headlight has a connecting drive cooperating with the vehicle steering gear so that the steering gear pivots the headlight in the same direction as, but with a greater angle than, the wheels of the vehicle. The connecting drive for each headlight includes a lever coupled with the steering gear and which performs a pivoting motion about its rotation axis following the steering motion, a fixed element connected to the headlight and a tie rod connecting the fixed element and the lever with spacing from the connecting point from the rotation axis.
In addition, an apparatus including a smaller additional rotationally mounted headlight is known for producing the direction-dependent portion of the illumination.
The problem with devices of the foregoing type is that they require a comparatively large amount of space for their pivoting or rotating parts. Furthermore they have a comparatively large weight and a comparatively large and massive mounting in order to take the comparatively large weight, retaining and drive forces.
Furthermore in order to be able to rotate the entire headlight a gap must be provided between the headlight component group and the covering frame connected with it, which permits rotation of the headlight. This kind of gap is considered to be undesirable in many cases because of its effect on the appearance of the headlight.
Finally also the portions of the light propagated from the rotatable headlight above the permissible light-dark boundary with low beam light, which also may then be rotated into the angular range, in which only certain light intensity values are allowed on account of the opposing traffic, are problematic or troublesome.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a headlight for a vehicle of the above-described type and an illumination device for a vehicle of the above-described kind, which do not have the above-described disadvantages.
It is a further object of the present invention to provide an illumination device for a vehicle of the above-described kind including at least two projection headlights, in which it is possible to rotate each headlight independently of each other with weight forces, retaining forces and drive forces that are smaller than with prior art rotatable headlights.
These objects and others, which will be made more apparent hereinafter, are attained in a projection headlight for a vehicle, especially a motor vehicle, which comprises a reflector, in whose peak region a light source is mounted, at least one stop or mask arranged in front of the reflector and a projection lens arranged in front of the at least one stop or mask.
According to the invention the projection headlight has a reflector and a light source, which are both pivotally mounted so as to rotate together about a rotation axis arranged in the vicinity of the second principal point of the projection lens.
These objects and others, which will be made more apparent hereinafter, are further attained in an illumination device for a vehicle, especially a motor vehicle, with at least two of the aforesaid projection headlights with respective rotatable reflectors and light sources.
According to the invention the illumination device includes means for rotating the respective rotatable reflectors independently of each other and according to a motion state of the vehicle.
In the projection headlight according to the invention only optical components that cooperate to shape or form part of the propagated light beam or light intensity distribution move, so that essentially smaller weight, retaining and drive forces arise, whereby the mounting arrangement for the reflector can be smaller. Moreover a motion gap between the headlight and the cover frame surrounding it can be dispensed with, since the projection lens is held in a fixed position during rotation of the beam-forming optical components. Because of the fixed stop or mask the above-described parts of the light beam or intensity distribution do not enter or reach an angular region in which only strict or limited light intensities tolerances are permitted on account of the opposing traffic.
The lighting device according to the invention has the advantage that optimum illumination of the vehicle travel path is provided by separately controlling the respective reflectors of the headlights according to the vehicle motion state in each travel situation.
Advantageous embodiments of the invention are also the subject matter of the dependent claims.
For example, in one embodiment of the projection headlight of the invention the rotation axis of the reflector is vertically oriented.
The stop or mask of the projection headlight of the invention is preferably formed to have a Petzval curvature with respect to the projection lens. Because of that shape for the stop or mask, on the one hand, the rotational motion of the reflector is not hindered or blocked. On the other hand, the distance between the reflector and the stop or mask can be kept small, so that the reflector can be comparatively large and can gather as much light as possible. Moreover the required sharpness and contrast of the light-dark boundary produced by the lens to by imaging the stop are sufficiently large independently of the direction of the light beam coming from the reflector.
In an additional advantageous embodiment of the invention the rotation axis is inclined toward the rear, above, relative to vertical, so that during rotational motional of the reflector its peak is moved upward. Thus the greater light intensities in the provided light distribution are brought closer to the vehicle. This accounts for that fact that vehicles usually traverse curves with reduced speeds so that the visible areas in front of the vehicles are desirably and appropriately brought closer to them.
In order to obtain the desired effect with headlights that are pivoted over comparatively large horizontal pivot angle ranges (e.g. ±25°), the rotation axis is inclined about 3° to 10° toward the rear. The inclination angles of up to 40° can be provided for headlights with a horizontal pivot angle range of ±10°.
Furthermore the rotation axis for the headlight of the invention can also be inclined laterally from the vertical transverse to or across the longitudinal axis of the vehicle. With right-hand traffic in the propagation direction the vertical axis is inclined, above, to the left but with left-hand traffic it is inclined to the right. In this way the reflector peak with the light source moves downwards during horizontal rotation to the left, whereby the maximum light intensities of the light intensity distribution from the headlight are propagated further from the vehicle. Thus when th
Husar Stephen
Robert & Bosch GmbH
Striker Michael J.
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