CA1213866A - Truncated motor vehicle headlamp - Google Patents

Abstract

TRUNCATED MOTOR VEHICLE HEADLAMP
ABSTRACT OF THE DISCLOSURE
A vehicle lamp, such as a headlamp or fog lamp, having a conave reflector truncated at its top and bottom, one of the truncated surfaces being closer to the optical axis than the other truncated surface, and both truncated surfaces being substantially non-reflective. This achieves significant glare control without requiring a separate shield between the light source and the reflector.

Description

fi~

TR~NCATED MOTOR VEHICLE HEADLAMP

BACKGROUMD OF THE I~VENTION
The invention i5 in the field of lamps for automobiles and other vehicles, such as headlamps and fog lamps, having truncated reflectors, i.e., reflectors having a concave surface which is truncated at the top and/or bottom.
Certain he~dlamp reflectors are truncated at their top and/or bottom to reduce their vertical height ror better fitting and styling in automobilesO In these and other types of headlamps, a shield or other means is used to achieve sharp beam cutof~ to reduce glare above the horizon-tal, specifically in low-beam l~mps used for city driving.
U.5. Pate~ts 1,359,789 to Brown and 4,276,583 to Fratty disclose truncated headlamps, in which Brown employs an auxiliary reflector and Fratty employs a shield ~o reduce glare.
Attempts to design truncated headlamps having reduced glaxe, without the use of internal shields, have not been completely succes~ful, especially where the filament i5 enclosed in a glass inner bulb.

SUM~RY OF THE INVENTION
Objects of the invention are to provide an improved and economical truncated vehicle lamp of compact size, without shielding the filament from the reflector, and which projects a light beam, wh~n installed on a vehicle, ~hat is substan-ti lly entirely below ~he horizvntal thereby signiicantly reducing glare~

The invention comprises, briefly and in a preferred embodiment, a vehicle lamp having a generally parabolic or concave reflector which is truncated at its top, bottom or sides, thus providing one or more flat sections substan tially parallel to the reflector's optical axis. The op~ical axis does not coincide with the center of the reflector. Furtharmore, the flat surface~ are non-reflective, such as by being transparent or light-absorbing. This con-struction achieves the desired improvement in glare reduction and elLminates the need for prior art filament shield.

BRIEF DESCRIPTION OF THE DRA~INGS
.
FIG. 1 is a front view o~ a headlamp in accordance with a preferred embodLment of the inventionO
FIG. 2 is a side sectional view taken on the line 2-2 of FIG. l.
FIG. 3 is a horizontal sectional view taken on the line 3-3 of FIG. l.

DESCRIPTION OF THE PREFERR~:D EMBODIMENTS
, ~
The headlamp comprises a reflector 11 having a generally parabolic or other concave reflectin~ surface 12 which may be a true parabola or a modified parabola configuration having an optical axis 130 A light bulb 14, preferably a halogen type, is held in the re1ector 11 by conventional or other suitable means, and contains a filament 16 or other suitable light source at or near the optical ~xis 13 and also at or near the focal point of the re1ector 12 so that the reflector 12 will reflect light from the light source 16 in a desired forward pattern a~ exemplified by the reflected light ray 17. If desired, the front top half of the bulb 14 may be rendered opaqu~, such as with a coating 18 of dark material, to block light rays that would emanate directly through the lens at an upward angle above the horizontal optical axis 13.

1~213B~

The top and bottom parts of the reflector 11 are truncated to form substantially flat top and bottom sections 21, 22 which may both be parallel to the optical axis 13.
A transparent cover plat~ or lens can be attached over the front opening of the xeflector in conventional manner. One of the flat sections, such as the top section 21, is con-sidera~ly closer to the optical axis 13 than is the other flat section 22, whereby the reflecting surface 12 is approximately a half section, or slightly widOE,of the more conventional symmetrical parabolic reflector. This provides more accurate beam design control of the reflected beam pattern and achieves substantial reduction of undesirable glare light above horizontal by eliminating the conventional parabolic upper half reflecting surface which, if present, lS would cau~e some glare light having an upward directional component~ The light source 16 should be frontwardly of the junction lines 21' and 22' of the flat section~ 21, 22 and the parabolic section 12, at least in the vicinity 22" of the vertical plane in which the light source lies, to prevent glare rays caused by light reflected from inner surface areas of the bulb, frontwardly of the light source, and re-reflected by the parabolic reflector surface.
In accordance with the invention, one or both of the top and bottom reflector sections 21, 22 are made so as to ~e substantially non re~lective of light. This can b~
accomplished by making them transparent, or of a light-absorbing material, or coating ~hem, preferably at their inner surfaces 23, 24, with a dark non~reflective material such as paint. The terms "non reflective" and "substan~ially non-reflective" as used herein mean that a surface has a low reflectivity so as to reduce glare in accordance with the invention, it being recognized that it is difficult or impossible ~o achieve absolutely zero reflectivity at a surface.

As has been described, the parabolic reflecting surface 12 reflects light rays from the light source 16 in a desired frontwardly direction, and, if desired, can be contoured to reflect some light downwardly and front-wardly to illuminate the road near the vehicle, none ofthis reflected light having a deliberate upward component which can cause glare for oncoming motorists. Also, some light from the light source 16 will ~roject directly frontwardly and downwardly through the front of the head-lamp adding to the nearby road illumination but not causingglare. As has been stated, the opaque coating 18 on the front of the bulb blocks and prevents direct glare light rays. Some light rays 26 from the source 16 are at an upward and rearward angle, and are not reflected by the non-reflective surface 23 because it is absorbed by its dark color or because it pas es through a transparent truncated section 21 and becomes trapped or absorbed by the vehicle hood or other structural members. If, however~ tne rays 26 were reflected at surface 23, they would follow a path 27, be re-reflected by surface 12 into a path 28, and again be re-reflected by surface 24 ~if reflecti~e) into a path 29 frontwardly and upwardly from the headl~mp thus causing undesired glare to oncoming motorists. There would be an infinite number of such undesired glare rays, reflecting at diverging angles, i.e., "fanning out" and sca~tering from the surfaces 23 and 24 and causing a wide-spreading projected beam of light having an undesirable upward glare component. Also, light rays reaching the front region of the lower surface 24 directly from the source 16 would, if this surface were reflective, be reflected with a glare-producing upward component. The invention, by pro-viding non-reflective characteristics at the truncated sections 21, 22, prevent3 ox substantially reduces the glare light. Numeral 31 indicate~ a light ray reflected by the LD 88~9 inner surface of the bulb 14 in an upward and rearward direction similar to the just-described ray 26, and which is not reflected by the truncated areas 21 and 22; if these areas were reflective, the ray 31 and others generally in the same direction would be multiply reflected and emerge as glare rays similar to ray 29.
The sides 32, 33 of the reflector can be truncated, if desired, to reduce the horizontal width, and may be either reflective or non-reflective because sideways (but not upward~ refle~ted rays are relatively unimportant.
Also, the light bulb 14, although shown horizontal, can be vertical or at another angle. Wi~h suitable redesign, the headlamp can be turned o~er so that area 22 is the top and area 21 is the bottom, the opaque coating area 18, if ~rovided, being relocated on the bulb to block direct front-ward light rays that would have an upward component through the front of the headlamp.
While preferred embodiments and modifications of ~he invention have been shown and described, various other embodiments and modifications thereof will become apparent to persons skilled in the art and will fall within the scope of the in~ention as defined in the following claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A vehicle headlamp for forward illumination substantially devoid of upwardly directed glare light, comprising a concave parabolic reflector member truncated at opposite side thereof to provide two generally flat top and bottom sections substantially parallel to each other and to the optical axis of a curved portion of the reflector member, and a light source contained within said reflector member, said light source being enclosed within a bulb and consisting of a single filament located adjacent the optical axis as well as the focal point of said reflector and further located frontwardly of the junction between said flat sections with said curved portion of the reflector member, said filament also being devoid of shield means blocking its light rays from being projected to the curved portion of the reflector member, both of said generally flat top and bottom sections being non-reflective and with said top section being substantially closer to said optical axis than said bottom section so as to substantially reduce the reflecting surface in said reflector member above said optical axis.