US3048734A - Non-glaring head lamps - Google Patents

Description

Aug. 7, 1962 H. LINNES NON-GLARING HEAD LAMPS Filed April 29, 1960 IN V EN TOR. 5%5/775/7/7 Lw/ms fizz w.

3,948,734 NGN-GLARING HEAD LAMPS Hermann Linnes, Walter-Flex-Strasse 1, Hannover, Germany Filed Apr. 29, 1960, Ser. No. 25,717 2 Claims. (Cl. 313-116) This invention relates to a non-glaring head amp pecially for motor vehicles.

The head lamps of the invention have a non-dazzling or non-glaring bulb and are characterized by the incandescent filament of the lamp being surrounded at a distance approximately equal to the size of the glass bulb by a layer of numerous transparent bodies directing the light from the incandescent filament chiefly perpendicularly to its direction of incidence. By this arrangement part of the light is deflected at an angle to the direction of incidence which can amount to as much as 90, i.e. tangentially to the surface of the glass bulb.

As compared with head lamps previously known this arrangement has the advantage that the field of view to the sides is illuminated to a Width of about 20 metres and immediately in front of the vehicle. To the front the field of view up to 60 or 80 metres distance is practically evenly illuminated whereas with the hitherto known head-lamps the illumination of the road ahead with dipped (dimmed) lights reached only 25 or at most 30 metres. By means of the screen of transparent particles the color of the light is varied from sharp white towards reddish-yellow, in the direct-ion of longer wavelengths. This gives better visibility especially in fog or mist. The light density was compared with the light thrown by hitherto known head-lamps is altered in the relation 2:1 so that an illumination intensity of 1 lumen in the presently known head-lamps will correspond to an illumination intensity of 2 lumens in the improved headlamps of the invention. Thus the illumination intensity will be below the maximum normally considered to be non-glaring. In the case of this type of head-lamp there is sometimes the disadvantage that the maximum usual input of the lamp, say 35 watts, will not provide a suificient illumination intensity on the road with dipped headlights. On the average there will be a deficiency of approximately 0.35 lumen on the road with dipped headlights.

To counter this disadvantage and to attain the desired illumination it is now proposed to leave a space on the upper surface of the lamp, down to approximately the horizontal level of the incandescent filament, free of any transparent light-diverting bodies. Preferably, this free space of clear glass should correspond to the surface of an ordinary two-filament bulb in the surface portion where the light rays are projected while in dipped position.

As a result, with dipped head-lights there will be no substantial difference compared to the usual dipped headlights screened by a shield, since the light rays from the dipper filament will pass through the clear glass area as in the case of clear glass bulbs and so reach the road through the appropriate (upper) part of the reflector.

The shape of the clear glass segment left open determines the size and direction of the rays. It is, of course, not necessary that the clear glass segment be exactl of the same shape as the surface through which the normal dipped light passed in prior bulb constructions, since in the case of the bulb of the invention there will be additional light given off from other parts of the glass bulb or the cover around it consisting of light-diverting transparent bodies which will also reach the road.

The screening of the filament for close lighting by means of the shield is not necessary since by the refrac- 3,048,734 Patented Aug. 7, 1962 tion of the light in the remainder of the bulb surface coated with the light deflecting bodies the glare effect is eliminated.

Also the illumination of the road by the long beam is improved by the proposed invention since part of the beam will be reflected without having passed through the refraction and glare dispersal enclosure or coating. Owing to the usual difference in the disposition of the close lighting coil and the distance lighting coil in relation to the focus of the reflector mirror, it follows that the rays from the distance light filament passing through the clear glass segment and reaching the reflector will be projected horizontally forward whilst the rays from the close lighting filament (dipper coil) passing through the clear glass segment to the reflector will be projected from the head-lamp at the usual downward angle. It has been found that there is no disturbing increase in the glare as is the case with head-lamps of prior constructions.

To obtain a somewhat brighter illumination of the right half of the road the clear glass segment on the left side of the bulb of the improved type can be enlarged to extend below the horizontal plane through the incandescent filament. Furthermore, an additional area of clear glass can be provided at the side of the lamp. In both cases the light from the coils will pass out sideways undeflected on the left side of the reflector whence it will pass mainly towards the right. In this manner the right hand side of the road will be fully illuminated and to a level which lies above a horizontal plane passing through the filament. The effect of this device approximates that of other known devices for producing asymmetric illumination. This facilitates recognition of traflic signs and other objects to the right of the road without dazzling oncoming motorists.

The improved lamp bulb can also be used with advantage in head-lamps of the existing type which include three blulbs that can be switched on separately or in combination. This type of head-light contains in addition to the parking light bulb, separate bulbs for clipped and for longbeam lighting. The use of the improved bulb of the invention in such headlights would involve leaving the long-beam bulb unchanged as a clear glass bulb with its longbeam filament. Besides this long beam bulb there would be the dipped light bulb with a dilferent setting in relation to the focus of the reflector. When using the improved incandescent bulb in this combination, part of the transparent light-deflecting enclosure will be removed, leaving an upper and lower clearglass segment on the bulb surface. Preferably, the lower segment should be smaller than the upper segment and pointing in the direction of the filament of the longbeam bulb. The larger segment, as already described, will point towards the upper part of the reflector. By this arrangement the rays from the long-beam bulb can pass through the lower and then through the upper clear segment spaces to reach the reflector from where they will be reflected in the usual manner. With this type of head-light there will be no glare when using the improved dipper bulb; it is avoided by the asymmetric arrangement.

When using the improved three bulb assembly an ideal long-beam light is provided when the dipper and longbeam bulbs are switched on together, for besides the long-beam lighting there will also be a very good, and by comparison with present lighting much improved, illumination in width of beam near the vehicle. It is also possible to switch on the long-beam and the dipped beam simultaneously from separate head-lamps.

Further details and advantages of the invention will become apparent from the following description together with the drawings, in which:

FIGURE 1 is a side elevational View, partly in section, of my improved design of incandescent bulb;

FIGURE 2 is a similar view of a lamp reflector showing the improved incandescent bulb in combination with separate bulbs for dipped and long-beam lighting; and

FIGURE 3 is a sectional view of a modified form of the invention employing a clear glass bulb and a separate external casing.

The improved incandescent bulb consists of a pearshaped glass bulb 2 fixed on a base 1. This glass bulb is provided on its outer surface with transparent light-deflecting bodies 3, as described below. It is, of course, also possible to place these transparent light-deflecting bodies not directly on the glass bulb but on a separate enclosure some distance from the bulb. At the side of the glass bulb pointing towards the upper side of the reflector a generally triangular-shaped segment 4 has been cleared of the transparent light reflecting bodies, thus consisting of clear glass. A similar segment 4 is provided on the other side of the bulb to provide a diamond-shaped area extending down each side to approximately the level of a horizontal plane through the incandescent filament. The dipper filament is marked with the reference number 5 and the long-beam filament with the reference numher 6 For use in right-hand traffic, for the better illumination of the right side of the road, there is on the left side of the bulb, somewhat below the point of the segment, an additional clear space 7 of elliptical shape through which the additional asymmetric illumination of the righthand half of the road is secured as earlier described.

In countries with left-hand traffic this clear space can be located correspondingly on the other side of the bulb.

In the example of design shown in FIGURE 2 the reflector R is fitted with a holding element 8 attached to the bottom of the reflector which serves to take the different bulbs. The bulb 9 is a parking light bulb, bulb 10 is a normal long-beam bulb of clear glass with only one incandescent filament 11 for the long-beam. The other bulb 12 corresponds to that described with reference to FIGURE 1. It consists of a clear glass envelope coated with transparent light-deflecting bodies 13. On its upper side there is a segment of clear glass 14 corresponding approximately to the segment 4 already described. The asymmetric clearing 7 is not shown.

Also, for the sake of simplicity, the dipper filament is not shown.

From the point of the clear space (segment) 14 in the direction of the filament 11 another smaller clear glass segment 15 extends downwardly. The points of the segments 14 and 15 meet at approximately the level of the dipper coil. By this arrangement the long-beam rays from incandescent coil 11 can also reach the upper part of the reflector. The effect in regard to the dipper light has already been described.

Owing to the displacement of the dipper bulb out of the focus line of the reflector, the light rays passing through the segment 15 will be so reflected by the reflector R that they will not be disturbed by the presence of bulb 12.

By covering the glass bulb or a casing surrounding the glass bulb with the transparent light-deflecting bodies 3 or 13 no screening shield for the dipper light filament is necessary. In neither of the drawings, therefore, is a dimming shield shown,

To be able to use the invention with conventional clear glass bulbs it is possible to fit them with a preferably split casing as shown in FIGURE 3. The lower part 16 of the casing with its neck 17 of clear glass can be drawn over the bulb base 1 close up to the glass bulb 2. The lower part of the casing 16 is held in place by the lamp socket into which the bulb is fitted. On this lower part towards the front a cap 13 is fixed and secured at the joint 21 by means of cementing, glueing or a threaded screw connection. The upper part 18 can be provided with a screen 19. In the screening 29 of the lower part an area 16 of clear glass has been left corresponding to the segment 4 in FIGURE 1 or the combination of segment 4 with the asymmetric clear space 7.

As shown in FIGURE 1 the outer surface of the clear glass bulb 2 or 12 (FIGURE 2) is covered with transparent light-deflecting bodies, except at the segment 4, 14- or 15 and the additional clear space of elliptical shape.

These light-deflecting bodies 3 are of a transparent material, preferably of glass, having been ground in a mill, e.g. =a roller-mill, to produce particles of pyramidal shape. These particles may be sifted or winnowed to collect those having a size of 1 to 2 mm., preferably however 1 mm. or less. These pyramidal particles are secured to the clear glass bulb by means of a suitable binder, e.g. glass having a low melting point.

Instead of adhering small pyramidal particles of the outer surface of the clear glass bulb the bulb itself can be provided with surfaces of pyramidal projections in that the bulb is stamped in a suitable die when the material of the bulb is still hot and plastic.

The pyramidal particles preferably should be positioned on the clear glass bulb such that they are in contact with their base with the surface of the bulb so that their apexes are pointing radially outwards.

Instead of grinding the glass in a mill the glass may be disintegrated by applying a pressure. By selecting the amount of pressure and the direction into which it acts as well .as the tension of the glass to be disintegrated it is relatively simple to obtain a sufficient amount of pyramidal particles of the desired size.

I claim:

1. A non-glaring head lamp comprising a filament, a clear glass bulb having a smooth interior enclosing said filament, said bulb being coated with a continuous layer of transparent light reflecting particles of pyramidal configuration having their bases overlying the external sur face of the bulb and their apices pointing outwardly, except for an area above the filament comprising -a diamond-shaped segment having its lower point terminating at each side of the bulb approximately level with the horizontal plane through said filament.

2. The head lamp of claim 1 in which said bulb has an additional clear glass area opposite said segment and extending laterally between the lowermost points thereof.

References Cited in the tile of this patent UNITED STATES PATENTS 730,852 Elliott June 3, 1903 1,348,617 Zorger Aug. 3, 1920 1,693,334 Beare Nov. 27, 1928 1,712,996 Hoffman May 14, 1929 1,977,613 Beck et al Oct. 23, 1934 2,011,677 Douglas Aug. 20, 1935 2,024,562 Bench Dec. 17, 1935

Images