Illumination – Supported by vehicle structure – Adjustable lamp or lamp support
Reexamination Certificate
1999-08-26
2001-08-28
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Adjustable lamp or lamp support
C362S513000, C362S284000, C362S324000, C362S428000
Reexamination Certificate
active
06280070
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a vehicle headlight which is designed to switch beams between low and high beams. More particularly, the invention relates to switching beams between low and high beams by tilting a reflector vertically by a predetermined angle.
2. Description of the Related Art
Vehicle headlights are designed to emit a low or high beam by causing light from a light source bulb to be reflected forward by a reflector. With respect to light sources (discharge light-emitting portions or filaments), though different light sources are generally used for low and high beams respectively because the direction of emitting the low beam differs from that of emitting the high beam, there are also known vehicle headlights using a single light source. Particularly in such a two-lamp type vehicle headlight using a discharge bulb as a light source bulb, a single light source arrangement will have to be made often.
In the case of a vehicle headlight using such a single light source, a low beam is switched to a high beam and vice versa by mechanically displacing optical elements including a light source bulb, a reflector and the like, and a beam switching device is installed accordingly because it is reasoned to use the beam switching device for switching beams by vertically tilting the reflector by a predetermined angle. By adopting the beam switching device, the actuator of a leveling unit can also be used as the actuator of the beam switching device.
However, the following problems will arise when such a reflector-tilting type beam switching device is introduced.
As a low-beam light distribution pattern, it is preferred to use a light distribution pattern P(L) having a clear cutoff line (a light-to-shade boundary line) CL as shown in
FIG. 14A
in view of securing forward visibility for automobile drivers as well as preventing a glare from those driving oncoming vehicles. When an attempt is made to switch beams by vertically tilting the reflector, however, the low and high beams are to be emitted with the same light distribution pattern. Consequently, the adoption of the light distribution pattern P(L) with the cutoff line CL as a low-beam light distribution pattern will result in providing a light distribution pattern P(H) having the cutoff line CL for a low beam as shown in
FIG. 14B
, thus developing the problem of failing to secure upward forward visibility (the portion shown by A therein) ahead of a vehicle.
SUMMARY OF THE INVENTION
An object of the present invention made in view of the aforementioned situation is to provide a vehicle headlight capable of switching beams between low and high beams by vertically tilting a reflector by a predetermined angle so that upward forward visibility ahead of a vehicle can be secured during high-beam traveling by using a light distribution pattern having a cutoff line as a low-beam light distribution pattern.
According to the present invention, it is intended to accomplish the object above by emitting part of the existing beam or a newly generated beam in the upward direction of a cutoff line in the way interlocked with the upward tilting of a reflector when a low beam is switched to a high beam.
Therefore, to achieve the above objective, there is provided, a vehicle headlight that includes the following: a light source bulb; a reflector for emitting a beam with a light distribution pattern having a cutoff line by reflecting light from the light source bulb forward; a lamp body for tiltably supporting the reflector; and a beam switching device for selectively switching beams between low and high beam by vertically tilting the reflector by a predetermined angle.
To further achieve the above objective, the vehicle headlight includes beam deflecting and emitting means for deflecting and emitting part of the beam to the vicinity of a position over the cutoff line in the way interlocked with the upward tilting of the reflector when the low beam is switched to the high beam.
Furthermore, to achieve the above objective, the vehicle headlight includes additional-beam generating means for generating a beam to be additionally emitted to the vicinity of the position over the cutoff line in the way interlocked with the upward tilting of the reflector when the low beam is switched to the high beam.
The aforementioned “light source bulb” for use is not limited to a specific kind of light source bulb but may be a discharge bulb, an incandescent bulb (including a halogen lamp) or the like, for example.
The aforementioned “predetermined angle” is such that the degree of the angle is not limited to a specific value as long as the vertical tilting by the predetermined angle allows the function of each of the low and high beams to be demonstrated; for example, the angle may be set at a suitable value (e.g., 3°) in the range of about 2-4° (or 2.5-3.5°).
REFERENCES:
patent: 4831506 (1989-05-01), Miyazawa
patent: 5197799 (1993-03-01), Dehaene
patent: 5993032 (1999-11-01), Herbers
patent: 6039466 (2000-03-01), Duchenne et al.
patent: 6059435 (2000-05-01), Hamm et al.
patent: 6161950 (2000-12-01), Tsukamoto et al.
Japanese Abstract No. 9092005 dated Apr. 4, 1997.
Ishida Hiroyuki
Kobayashi Shoji
Ohshio Hirohiko
Hobden David V.
Koito Manufacturing Co. Ltd.
O'Shea Sandra
Sughrue Mion Zinn Macpeak & Seas, PLLC
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