This application claims the priority benefit under 35 U.S.C. ยง119 of Japanese Patent Application No. 2007-283496 filed on Oct. 31, 2007, which is hereby incorporated in its entirety by reference.
1. Technical Field
The presently disclosed subject matter relates to a mount structure for use in electric lamps, and more particularly to a mount structure for use in electric bulbs of the double-filament type for use in vehicular headlamps.
2. Description of the Related Art
The inner leads 52a, 52b for supporting the low-beam filament 52 linearly extend a certain length from a bridge 53 in a direction substantially (exactly or almost) normal to the bridge 53 and have respective ends connected to ends of the low-beam filament 52.
On the other hand, the inner leads 51a, 51b for supporting the high-beam filament 51 are held at the bridge 53 inward from the pair of inner leads 52a, 52b. The inner leads 51a, 51b extend a certain length linearly from the bridge 53 in parallel with the inner leads 52a, 52b. They are then bent and extend a certain length linearly away from the bridge 53 outward (toward the positions of the inner leads 52a, 52b). They are bent again and extend a certain length linearly in parallel with the inner leads 52a, 52b. The ends of the inner leads 51a, 51b are connected to the ends of the high-beam filament 51.
As shown in
Referring again to
Such reflected light (diffused light L) from the folded portions 58 transmits out of regular optical pathways to a reflector 60 having an inner reflecting surface and an outer lens 61 having appropriate lens-cuts for optical path control, as shown in
As shown in
The presently disclosed subject matter has been made in consideration of the above characteristics, features and problems and can be configured to provide a technology for a double-filament type lamp in which inner leads for supporting a high-beam filament are prevented from reflecting light emitted from a low-beam filament. This makes it possible to prevent unwanted occurrences of diffused light which do not contribute to formation of the low-beam distribution pattern but rather exerts ill effects. This is effective to form an optimal light distribution pattern.
The disclosed subject matter also includes a lamp that can be configured to prevent outer leads from intersecting and thus avoiding a possible electrical short-circuit when plural terminals are provided in a certain array on a tube base and are connected to the leads.
According to a first aspect of the disclosed subject matter a mount structure for a lamp can include: a low-beam filament and a high-beam filament contained in a substantially cylindrical glass bulb of an electric bulb; a pair of first leads having respective one side ends to which both ends of the low-beam filament are connected and supported thereon; a pair of second leads having respective one side ends to which both ends of the high-beam filament are connected and supported thereon; and a lead holder between which the other ends of the four leads are held in line, wherein the low-beam filament locates in a first plane containing an optical axis located on the almost same line as the central axis of the glass bulb, facing in a direction orthogonal to the optical axis, wherein the high-beam filament locates in a second plane normal to the first plane and almost in parallel with the low-beam filament, wherein the pair of first leads locate between the lead holder at positions sandwiched between the pair of second leads and locate almost in the first plane between the low-beam filament and the lead holder, wherein the pair of second leads locate in a third plane defined in parallel with the optical axis and substantially normal to the first plane between the high-beam filament and the lead holder.
According to a second aspect of the disclosed subject matter, the pair of first leads include at least two folded parts formed between the low-beam filament and the lead holder, wherein the pair of second leads include at least two folded parts formed between the high-beam filament and the lead holder.
According to a third aspect of the disclosed subject matter, the pair of first leads and the pair of second leads include a pair of leads located adjacent to each other at the lead holder and connected together to configure a common earth lead, the mount structure further comprising a bulb base having a common earth terminal, a low-beam filament terminal, and a high-beam filament terminal, wherein the common earth terminal is connected to the common earth lead, the low-beam filament terminal is connected to one of the pair of first leads, and the high-beam filament terminal is connected to one of the pair of second leads.
According to a fourth aspect of the disclosed subject matter, the glass bulb encloses a halogen gas or a halogen compound gas.
In an exemplary mount structure for an electric bulb according to the disclosed subject matter, the low-beam filament can be arranged in the horizontal reference plane containing the optical axis X of the glass bulb, facing in a direction orthogonal to the optical axis X. The high-beam filament is arranged in a plane normal to the horizontal reference plane and in parallel with the low-beam filament. The pair of inner leads for supporting the low-beam filament is located in the horizontal reference plane. The pair of inner leads for supporting the high-beam filament is located in a plane defined in parallel with the optical axis X and normal to the horizontal reference plane.
As a result, it is possible to prevent the inner leads which support the high-beam filament from reflecting light emitted from the low-beam filament. This makes it possible to prevent the creation of unwanted diffused light, which does not contribute to formation of the low-beam distribution pattern and rather can exerts ill effects on lamp output characteristics. This is effective to form an optimal light distribution pattern.
In addition, the arrangement of the pair of leads for supporting the low-beam filament and the pair of leads for supporting the high-beam filament is aligned with the arrangement of the terminals on the bulb base.
As a result, it is possible to prevent the outer leads from intersecting, thus avoiding a possible electrical short-circuit.
Certain exemplary embodiments of the disclosed subject matter will now be described in detail with reference to
The low-beam filament 5 has a longitudinal/central axis Yb, which can be located in a substantially horizontal reference plane H in the electric bulb 2. The bulb 2 can have an optical axis X located on the same or possibly parallel line as the central axis of the glass bulb 3. The longitudinal/central axis Yb extends in a direction substantially orthogonal to the optical axis X. The high-beam filament 4 has a longitudinal/central axis Ya, which can be located in a plane normal to the horizontal reference plane H, substantially in the same plane shape as the central axis Yb of the low-beam filament 5, and in parallel with the central axis Yb (see
The high-beam filament 4 has ends which are each connected to and supported on respective side ends of the inner leads 4a, 4b. The low-beam filament 5 has ends which are each connected to and supported on respective side ends of the inner leads 5a, 5b.
The bridge 6 can be configured as a lead holder and can include a pair of glass columns 6a, 6b composed of glass, which can be configured as substantially columnar shapes provided in parallel. The longitudinal direction thereof can be substantially parallel with the longitudinal/central axis of the high-beam filament 4 and the longitudinal/central axis of the low-beam filament 5. The inner leads 4a, 4b, 5a, 5b have middle portions, which are sandwiched between the pair of glass columns 6a, 6b and held in line.
The pair of inner leads 5a, 5b for supporting the low-beam filament 5 are sandwiched and held at the bridge 6 inward from the pair of inner leads 4a, 4b which support the high-beam filament 4. The whole lines of the inner leads 5a, 5b extending from the bridge 6 to the ends of the low-beam filament 5 can be substantially located in the horizontal reference plane H.
At the same time, the inner leads 5a, 5b extend a certain length Lb1 linearly from the bridge 6 in a direction parallel with the optical axis X. The leads 5a, 5b are then bent and extend a certain length Lb2 linearly away from the bridge 6 and outward (toward the positions of the inner leads 4a, 4b). They are bent again and extend a certain length Lb3 linearly in a direction parallel with the optical axis X. The ends of these inner leads 5a, 5b are then connected to the ends of the low-beam filament 5.
On the other hand, the pair of inner leads 4a, 4b which support the high-beam filament 4 extend a certain length La1 linearly from the bridge 6 in a direction parallel with the optical axis X. The leads 4a, 4b are then bent and extend a certain length La2 linearly in the direction normal to the longitudinal direction of the bridge 6 downward (toward the position of the high-beam filament 4). They are bent again and extend a certain length La3 linearly in the direction parallel with the optical axis X. The ends of the inner leads 4a, 4b are then connected to the ends of the high-beam filament 4.
The length La1 of the inner leads 4a, 4b is not always required to be equal to the length Lb1 of the inner leads 5a, 5b. The difference between the length La1 the length Lb1 does not necessarily exert influence on the optical characteristic (e.g., the light distribution characteristic) of the electric bulb 2.
As can be seen from
Therefore, light emitted from the low-beam filament 5 toward the metal-free zone Mf is not blocked by any one of the inner leads 4a, 4b, 5a, 5b. Accordingly, it is possible to suppress the presence of light (diffused light) traveling on the optical path that exerts ill effects on the formation of the low-beam distribution pattern.
As a result, the reduction in this unwanted diffusion light which is incapable of contributing to proper formation of the low-beam distribution pattern results in a light distribution pattern capable of providing bright and excellent visibility with high utilization of light. It is also possible to reduce dazzling or glaring light directed at oncoming traffic, which is an obstacle for drivers of on-coming vehicles. Therefore, the configuration of the mount structure 1 can contribute to safe driving of vehicles.
An electric bulb 2 having the above-configured mount structure 1 can be completed after being fixed to and held on a bulb base. As shown in
On the other hand, in the electric bulb 2, the pair of inner leads 4a, 4b which are electrically connected to the high-beam filament 4 can be configured to lead out straight from the glass bulb 3 to form outer leads 4aa, 4bb. In addition, the pair of inner leads 5a, 5b which are electrically connected to the low-beam filament 5 can be configured to lead out straight from the glass bulb 3 to form outer leads 5aa, 5bb. The outer lead 4bb is connected with the outer lead 5bb to form a single common earth outer lead 8. The common earth outer lead 8, the outer lead 5aa for the low-beam filament, and the outer lead 4aa for the high-beam filament are arrayed in turn from one side of the bulb 2.
The common earth terminal (j) on the bulb base is configured for connecting to the common earth outer lead 8 of the electric bulb. Similarly, the low-beam filament terminal (i) on the bulb base 7 is configured for connecting to the outer lead 5aa for the low-beam filament, and the high-beam filament terminal (h) on the bulb base 7 is configured for connecting to the outer lead 4aa for the high-beam filament. Even in this case, it is possible to prevent outer leads from intersecting with each other and to avoid an occurrence of an electrical short-circuit.
While there has been described what are at present considered to be exemplary embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover such modifications as fall within the true spirit and scope of the invention. All conventional art references described above are herein incorporated in their entirety by reference.
Number | Date | Country | Kind |
---|---|---|---|
2007-283496 | Oct 2007 | JP | national |