JPS5998401A - Lamp for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a vehicle lamp, and more particularly to a vehicle lamp having improved heat shielding means.

U.S. Pat. No. 4,280.173 and U.S. Pat. No. 4,210.
841, heat shielding means are already known for use in headlights of rectangular construction, made entirely of plastic. The heat shielding means described in the first mentioned US patent consists of a metal plate interposed between the lamp filament and the lamp roof. The flat surfaces forming the roof and floor of the cut-out reflector are generally parallel to each other and at the same distance from the optical axis of the lamp.

In the later-granted U.S. patent, the heat shielding means
A substantially planar heat reflecting member is also interposed between the light source filament and the lamp roof by suspending it from the lamp roof. The effect achieved by both types of heat shielding means is to prevent the filament of the lamp from convection as well as radiant heating due to the generation of a wall temperature in the area above the filament close to or above the softening point of the plastic. It is.

Generally of this type, however, even lamp constructions in which there is little free space above the lamp filament to permit the interposition of separate heat shielding means,
It is desirable to have the same advantages. More specifically, the low profile cutaway motor vehicle lamp described in pending U.S. Patent Application Ser. Since the surfaces are much closer to the lamp filament, no thermal shielding means can be interposed therebetween. Conventional headlights made entirely of glass can solve the problem of distortion due to heat, but the heating of the roof surface in these headlights by convection and radiation is not as good as conventional headlights made entirely of plastic. It will be appreciated that this is a much more serious problem than the PAR lamp. Accordingly, an all-plastic headlamp of the type described in the above-cited U.S. Pat. It requires that.

Therefore, one important object of this invention is to provide an all-plastic PAR lamp for low height rectangular vehicle lighting.
It is an object of the present invention to provide a lamp with effective heat shielding means.

Another object of the invention is to provide a heat shielding means for an all-plastic headlamp of this type which has a more effective means of removing heat from the inner envelope of the lamp.

Another object of the invention is to provide the heat shielding means, when molded, as an integral part of the roof of the reflector.

Briefly, the invention relates to a lamp for a vehicle in which the heat shielding means forms an integral part of the flat roof portion of a reflector member used in a plastic headlamp of the type described above. . In a preferred embodiment, a metal insert is placed in the flat plane of the roof directly above the filament of the light source;
Ensures that the plastic reflector member is held in place when molded. Providing additional heat transfer means such as cooling fins or corrugations in the metal insert further improves the removal of heat from the inner envelope of the lamp and prevents the lamp from penetrating with ambient moisture. Physical distortions that are familiar to premature failure can be avoided.

The present invention provides a concave reflector having two generally flat portions cut out on both sides and substantially parallel to each other and to the optical axis of the curved portion of the reflector, and a concave reflector housed within the refractor. a filament light source enclosed within a tube, with one generally flat portion much closer to the optical axis than the other, to substantially eliminate upward glare. An improved vehicle headlamp for forward illumination, in which the reflector is made of a synthetic polymer, and a heat shielding means is provided which forms part of a flat area closer to the light source. The Company provides headlights for vehicles with a

As previously mentioned, the lamp of the preferred embodiment has a reflector member molded from a synthetic organic polymer and a metallic heat shield means molded into the flat portion closer to the light source.

Another method of bonding the metal heat shield to the reflector member is to use a structural adhesive.

A typical cutaway motor vehicle headlamp of all plastic construction with improved heat shielding means of the present invention has a reflector 11. The reflector 11 has a generally parabolic or other concave reflecting surface 12, which may be a true paraboloid or a modified paraboloid. , has an optical axis 13. A tube 14, preferably of the glass-halogen type, is held within the reflector 11 by conventional or other suitable means and is located at or near the optical axis 13 and at or near the focal point of the reflective surface 12. having a filament 16 or other suitable light source and a reflective surface 1;
2 reflects the light from the light source 16 in a desired forward direction, as illustrated by a reflected beam 17. If desired, the upper front half of the tube 14 can be made opaque by a coating 18 of a dark material, and the upwardly directed corner bar above the horizontal axis 13 can block the light rays directly exiting the lens.

The top and bottom portions of the reflector 11 can be cut away to form generally flat upper and lower portions 21,22. Both of these parts can be parallel to the optical axis 13. A transparent cover plate or lens (not shown), also of synthetic organic polymeric material, can be mounted in the conventional manner over the front opening of the fouler. One flat part, such as the upper part 21, is closer to the optical axis 13 than the other flat part 22, so that the reflective surface 12 has a normal symmetrical paraboloid shape. It is approximately half the width of a surface reflector, or slightly wider. When covered like this, the reflected beam
The beam design of the pattern is precisely controlled and eliminates the irregular surface in the upper half of a normal paraboloid, which would otherwise produce glare with an upward component. By eliminating it, undesirable above-horizontal glare can be substantially reduced. The light source 16 is arranged in front of the light source at least in the vertical plane in which the light source lies, in order to prevent glare caused by the light reflected from the inner surface area of the bulb being reflected again by the paraboloid of the reflector. Near 22", the flat portion 21.
22 and the joining line 21', 22' between the paraboloid section 12
It should be closer to the front.

In order to better obtain glare-free illumination with this lamp construction, one or both of the upper and lower parts 21, 22 can be made non-reflective. To this end, they can be made transparent or made of light-absorbing polymeric materials, or preferably their inner surfaces 23.24
may be coated with a dark non-reflective material such as paint. As used herein, the terms "non-reflective" and "substantially non-reflective" mean that the surface is a source of low reflectance to reduce glare in accordance with the desired purpose.

It is well known that it is difficult or impossible to reduce the reflectance of a surface to absolutely zero.

As previously mentioned, the parabolic reflector 12 reflects the light rays from the light source 16 in the desired forward direction, but may also reflect some light downward and forward, to illuminate the road near the axle, if desired. This reflected light can be contoured so that no part of this reflected light has a noticeable upward component that causes glare to oncoming drivers. Some light from the light source 16 is projected directly forward and downward through the front lens of the headlight, helping to illuminate nearby roads but not causing glare. An opaque covering 18 on the front side of the bulb blocks and prevents direct glare. Some light rays 26 from light source 16 are angled backwards and upwards and are not reflected by non-reflective surface 23. This is because this light ray is absorbed by the dark color or passes through the transparent cutout 21 and is captured or absorbed by the vehicle's shroud or other structural member.

However, when rays 26 are reflected by surface 23, such rays follow a path 27, are reflected by surface 12 to path 28, and by surface 24 (if reflected) are directed forward and upward from the headlight. It is reflected onto the path 29, thus causing undesirable glare to oncoming drivers.

Such undesirable glare rays are infinite and are reflected at divergent angles, i.e., "fan out", and are scattered at surfaces 23 and 24, resulting in a widely spread projected light beam with an undesirable upward glare component. It causes. light source 1
If this surface is reflective, the light rays reaching directly from 6 to the front region of the lower surface 24 will also be reflected with an upward component producing glare. For this reason, the cut out part 21.
By providing 22 with non-reflective properties, glare is prevented or substantially reduced. Number 31 is tube 14
shows a ray of light that is reflected backwards and upwards by the inner surface of , similar to the ray 26 previously mentioned, which is not reflected by the cut-out portions 21.22. If such an area is reflective, ray 31 as well as other rays of generally the same direction will be reflected many times and exit as a glaring ray similar to ray 29. In the illustrated embodiment of the lamp, the sides 32,33 of the reflector can be cut to reduce the horizontal width and can be reflective or non-reflective, if desired. This is because reflected rays that are sideways (as opposed to upwards) are less of a problem.

The bulb 14 is shown horizontally, but if the area 18 of opaque coating is to be provided vertically or at another angle, this should be repositioned on the bulb so that it is oriented upwardly relative to the front side of the headlamp. Make sure to block direct, forward-looking light that has components.

As previously mentioned, the present invention provides a thermal shielding means 34 as an integral part of the flat portion 21 of the reflector closer to the light source in the lamp of the previous embodiment. More specifically, placing the heat shield itself within the aforementioned plastic material, preferably at a location directly above the lamp filament, not only avoids softening of the plastic at this location, but also absorbs this heat. dissipates from inside the lamp envelope 9. The planar metal disc 35 can be used as a heat shielding member in that it has a higher melting point and higher thermal conductivity than those obtained with thermoplastic organic materials used to mold plastic reflector members. It can work. The metal disc 35 is capable of conducting heat laterally through the surrounding plastic material as well as into the surrounding atmosphere; This can be improved by intervening a heat insulating part 36 made of a synthetic resin having a higher melting point as an integral part.

Thermoplastic organic polymers suitable for use in forming the reflector members of this invention can be selected from transparent or opaque thermoplastics having a heat strain humidity greater than 130°C; - Contains polycarbonate copolymers, polysulfones, filled phenolic resins, polyetherimides, and polyphenylene sulfide resins, such as those sold under the trade name "Lexan" by Electric Company. Representative of suitable thermoplastic resins with higher melting points suitable for use as insulation barriers in the thermal shielding means of this invention include polyphenylene sulfide with a heat distortion temperature of 260°C and above and a heat distortion temperature of at least 180°C. Certain phenolic thermoset materials may be selected as commercially available.

FIG. 4 shows a particularly preferred heat shield member for use with the present invention. The heat shield has a lip for attaching to the roof of the plastic reflector and additional cooling structure to remove heat from inside the lamp envelope.

Specifically, the metal heat shield member 34' is in the form of a planar disc 35' having a suitable contour to fit into an opening in the roof of the reflector, and which has a suitable contour to fit into an opening in the roof of the reflector. It has end pieces 37', 38' which engage slots provided in the. To help remove heat from the enclosed reflector instead of conducting it laterally into the surrounding plastic material, a series of parallel aligned ribs 39' (not shown) are provided on the outside of the planar disk. ) is provided.

From the foregoing description, it will be understood that the heat shielding means of the present invention may be modified in other ways than specifically described herein without departing from the scope of the invention.

For example, the metal heat shield member may have another shape, such as circular, or it may be enlarged to form a portion of the rear curved surface of the reflector member. It is, therefore, to be understood that the scope of the invention is limited only by the following claims.

[Brief explanation of the drawing]

FIG. 1 is a front view of a headlamp according to a preferred embodiment of the invention;
2 is a side cross-sectional view taken along line 2-2 in FIG. 1; FIG. 3 is a horizontal cross-sectional view taken along line 3-3 in FIG. 1; and FIG. 4 is a preferred thermal shielding member with cooling fins. This is a diagram. Explanation of main symbols 11: Reflector 12: Reflective surface 13: Optical axis 16: Filament 21.22: Flat portion 3z: Heat shielding means Patent applicant

Claims (1)

[Scope of Claims] 1) A concave reflector whose opposite sides are cut out to obtain two generally flat parts parallel to each other and to the optical axis of the curved part of the reflector; and a filament light source housed within the reflector, the light source being enclosed within a bulb, one of the generally flat portions being much closer to the optical axis than the other. In a vehicle lamp for forward illumination with substantially no upward glare, the reflector is formed of a synthetic organic polymer and a flat portion closer to the light source is provided. A vehicle lamp having heat shielding means forming a part thereof. 2. In the vehicular lamp according to claim 1), the light source includes at least a reflective portion of a reflector in the vicinity of a vertical plane where the light source is located and a cut out entirely flat portion. A vehicular lamp positioned substantially on the optical axis in front of the connecting portion of the vehicle. 3) A vehicle lamp according to claim 1), wherein both generally flat portions are substantially non-reflective to the light generated by the light source. The vehicular lamp according to claim 1, wherein the heat shielding means is constituted by a flat metal member disposed above the filament. 5) The vehicle lamp according to claim 4, wherein the planar metal member includes thermal insulation means disposed at the connection between the polymer and the metal. 6)'A concave reflector with two generally flat parts cut away on both sides thereof and substantially parallel to the optical axis of the curved part of the reflector and to each other, and housed within the reflector. having a filament light source, the light source being enclosed within a bulb, with one generally flat portion being much closer to the optical axis than the other, and a curved portion of the light source and reflector In a vehicle lamp that illuminates the front without providing any light shielding means in between and substantially eliminates upward glare, the reflector is molded of a synthetic organic polymer and the light source is further A vehicular lamp with a metal heat shield molded onto a flat area in close proximity. 7) The vehicular lamp according to claim 6, wherein the heat shielding means is composed of a flat metal member. 8) The vehicle width lamp according to claim 6), wherein the heat shielding means includes a heat transfer means. 9) The vehicular lamp according to claim 8), wherein the heat shielding means is constituted by a corrugated metal member. 10) The vehicular lamp according to claim 7), wherein a heat insulating means is provided at the connection portion between the polymer and the metal.