Patent Application
20090086501
not applicable
1. Field of the Invention
The invention relates to electric lamps and particularly to electric lamps. More particularly the invention is concerned with lamps with a plurality of enclosed filaments.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Advanced forward lighting headlamp systems (AFS) are being developed to light the road on the side a vehicle is turning to. The first AFS headlamp systems used one lamp and one reflector or projector lens. The beam control was achieved by rotating the entire lamp to the right or left with a stepper motor. This is a mechanically complex and expensive system. Alternative systems were devised using a first lamp to generate a forward beam and a second lamp to generate an augmenting side beam in response to a turning signal. By tuning between the two sources one can aim the beam. The two lamp AFS systems may use either or both two light sources, and two reflectors. The cost of the extra material for the lamps and the reflectors, the space and volume for the second lamp, and the additional labor in mounting, and aiming the duplicative systems makes the enhanced lighting system expensive.
An incandescent lamp capsule may be made with an envelope having a light transmissive wall defining an enclosed volume, and a lamp axis. A first filament is positioned in the enclosed volume having a first filament axis. The first filament is oriented so the first filament axis is in an axial plane parallel with the lamp axis. A second filament is also positioned in the enclosed volume, defining a second filament axis. The second filament is oriented so the second filament axis is in the axial plane; and the second filament axis is not parallel to the first filament axis. A third filament is positioned in the enclosed volume, defining a third filament axis. The third filament is oriented so the third filament axis is in the axial plane with the first filament axis and the second filament axis. The third filament axis is not parallel to the first filament axis, and the third filament axis is not parallel to the second filament axis.
Enclosed in the envelope volume is a first filament 50 extending along a first axis 52. The first filament 50 may be a straight wire extending as the axis 52; a wire coiled around the axis 52, a coiled coil extending along the axis 52, or similarly formed linearly extending filament structure. In general, the first filament 50 is linearly extended along the first axis 52, and is symmetrically disposed about the first axis 52, to form an approximately cylindrical filament structure. The first filament has a first electrical connection 54 and a second electrical connection 56. The first filament is mechanically and electrically supported between a first support 58 and a second support 59.
Enclosed in the volume is a second filament 60 extending along a second axis 62. The second filament 60 may also be a straight wire extending as the second axis 62, a wire coiled around the second axis 62, a coiled coil extending along the second axis 62, and so on in the same pattern. In general, the second filament 60 is linearly extended along the second axis 62, and is symmetrically disposed about the second axis 62. The first axis 52 and the second axis 62 are in a common plane, but are not parallel. The second filament 60 then extends in a common plane (Actually the filaments are in a common parallel planar slice that is co-planar with their respective axes. The slice has a width equal to the filament diameter, but for convenience the filaments will be said to be “parallel” or in a common plane.) with the first filament 50, but in a direction with at least a component direction that is perpendicular to the first axis 52. The second filament has a first electrical connection 64 and a second electrical connection 66. The right side filament 60 is coupled mechanically and electrically between the third support 68 and a fourth support 69. In one preferred embodiment, the right side filament 60 forms a right angle with the first filament 50 at the rear end of the first filament 50. The second filament 60 is then substantially behind the first filament 50 (closer to the base 82), minimizing interference with the function of the first filament 50.
Enclosed in the volume is a third filament 70 extending along a third axis 72. The third filament 70 may also be a straight wire extending as the third axis 72, a wire coiled around the third axis 72, a coiled coil extending along the third axis 72, and so on in the same pattern. In general, the third filament 70 is linearly extended along the third axis 72, and is symmetrically disposed about the third axis 72. The first axis 52 and the third axis 72 are in a common plane but are not parallel. The third filament 70 then extends in a common plane (actually in a planar slice with a width of the filament diameter) with the first filament 50, but in a direction with at least a component direction that is perpendicular to the first axis 50. The third filament 70 has a first electrical connection 74 and a second electrical connection 76. The left side filament is coupled mechanically and electrically between the fifth support 78 and a sixth support 79. The third filament 70 may form a right angle with the first filament 50 at the rear end of the first filament 56. The third filament 70 is then substantially behind the first filament 50 (closer to the base 82) minimizing interference with the function of the first filament 50.
The first support 58, second support 59, third support 68, fourth support 69, fifth support 78, sixth support 79 may be captured in a glass bridge 80, and then extended through a press sealed end 82 of the lamp envelope for electrical connection on the lamp exterior. The second support 59, fourth support 69 and sixth support 79 may be combined (pairwise or as a triple) to form a single support (common electrical supply).
The lamp is operated by supplying electrical energy to the first filament to generate light. The light generated by the first filament (50, 100) is then directed by the reflector to be centered about a desired point in the field to be illuminated. When the vehicle is steered under a first condition to a one side relative to the beam generated by the first filament (50, 100), a first turning signal is generated that is used to signal the supply of electrical energy to the second filament (60, 110). The actual first turning signal may be generated as a function of one or more steering factors such as an absolute change, a rate of change, a duration of change, a time integrated change, some other signal indicating a change in the vehicle relative to the environment or a computed combination of such factors. The vehicle condition change signal is then used to drive the electrical energy supplied to the second filament (60, 110) or to the third filament (70, 120). For example, if the vehicle is turned to the right, the second filament (60, 110) located on the left of the first filament is turned on to generate light that is then reflected by the reflector to the right side (assuming an inverting reflector) of the beam pattern generated by the first filament (50, 100) and the reflector. It is understood there may be beam over lap between the reflected beam from the first filament, and the reflected beam from the second filament. The sensed actual turn on signal may be conditioned by other computed factors, such as the angle of turn, rate of turn, duration of turn angle, vehicle speed of or other measured or computed factors. The light from the second filament (60, 110) then further illuminates the right side of the field to be illuminated in the region where the vehicle is turning to. The third filament (70, 120) may be farther to the left of the first filament and the second filament (60, 110), and is sequentially illuminated when the turning factors indicate still more light is needed even farther to the right, for example when a particularly sharp turn is made and extra light is desired far to the side of the first beam pattern. Alternatively, the third filament (70, 120) may be located on the right side of the first filament (50, 100), which is on the opposite side of the first filament (50, 110) relative to the second filament (60, 110). The third filament (70, 120) may then be similarly connected to be illuminating when a left turn (opposite to a right turn) is sensed. Again the third filament (70, 120) may respond to the turn angle, the rate of turn, the duration of the turn a so on. In this way the main beam of the first filament is supplemented by the light from the second or third filaments, directed substantially in the same plane or planes, as is light for the first filament, but to a side of the center of the beam from the first filament.
It is understood the main filament axis need not be axially centered along the main axis of the envelope, but may be radially offset from the main envelope axis. It is also understood that the lamp may be reoriented with respect to the field to be illuminated by restructuring the headlamp reflector accordingly. In general the second filament and the third filament may be positioned around the lamp axis in any position, given that the associated surrounding reflector directs the associated light appropriately to the right and left sides of the filed to be illuminated accordingly. One simple variation is to rotate the lamp 180 degrees, and rework the reflector to project the light from right (now left) and left (now right) side filaments across the beam axis line to the respective opposite sides of the illuminated field. More complex redirections can be achieved with a vertical orientation, that is changing from a 3 o'clock to 9 o'clock orientation to a 12 o'clock to 6 o'clock orientation or any intermediate orientation. While there have been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention defined by the appended claims.
