US 1393573 A
Description (OCR text may contain errors)
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N 1. A. RITTER.
APPLICATION FIL-EDLOCT. 2l, 1920.
1,393,573; Patented oct. 1i, 1921.
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JOHN A. RITTER, or LaNsnovvNnI 1=ENNsYrfvf1N1.a.-
Specification of Letters Patent.
Application led etober-` 21, 1920. Serial No. 418,396.
'State of Pennsylvania, have invented certain neu/Land useful Improvements in Headlampsand I herebyT declare that the following is a full, clear and exact description thereof, reference being hadto the accompanying drawings, which form part of this specification. y
My invention relates particularly to head lamps on moving vehicles, such as automobiles, railway locomotives, interurban electric cars and the like, and it improves the art by providing means for reducing the glare from such head lamps without reducing the intensity of the illuminating beam of light.
By glare I mean theA side light which issues from the front glass of an ordinary head lamp in a widely divergent cone and which is so annoying and even dangerous to persons who are compelled to approach and pass within a few feet of such a head lamp, as in automo ile driving. Most of this glare is direct (not reflected) light from the lamp filament, which, of course` is heated to dazzling incandescence, and I do not refer to the glare that would be produced by the reflected beam cone of light from a head lamp or spot-light that happens to be improperly pointed to the right or left of its proper path.. A beam of light powerful enough to illuminate a highway at a considerable distance mustof necessity be blinding to theunshaded eye, and the laws of many States take this into account and prohibit the re-` ilected beam cone from an automobile head lam to rise more than a few feet above the roa [Even thoughl this adjustment ism-made, however, the scattered light cone from the present type of head lamp is powerful enough to produce dangerous glare, andmy invention permits the complete control of this light so that it may be directed in any desired manner.
Referring to the drawings y Figure l is a vertical cross section of a head light embodying my invention.
Fig. 2 is a modification in which three different treatments of 'the rays are provided for.
Referring more particularly to the drawings; A, denotes an elliptical reflectonthe elliptical surface of which is formed to reflect the light rays to given central points in front of the reflector; F, denotes a point at which the reflected rays would meet if iio lens were interimposed. X-X reprerafented oct. 11, 1921.
sents the center aXis'of the light rays and passes through the foci L and 4. B, represents a convex lens formed as shown in the drawings of prisms arranged in circles of varylng diameter for transmitting direct radiating rays in horizontal lines; 7), is a double concave lens; C, represents a non-reflecting surface or outer ring adapted to absorb light rays not otherwise provided for in my invention.
The lines G and g denote the path of di-` rect rays. The lines H, show the path of the reflected rays. Y
In the modification shown in Fig. 2, b2 denotes a plain glass through which pass direct rays, without refraction. The path of these rays is denoted by the lines g.
A given lens can of course, only give definite direction to a group of rays that fallv ceeding directly from the light source L,-
being transmitted by the convex lens B, being refracted thereby so that they emerge in a beam parallel to the axis of the reflector.
The second series of rays marked H, are
reflecteed from the reflector A. This series 4 is by far the largest. These rays would converge on the focus F; but the do'ble concave lens b transmits these rays and refracts them so that they emerge in rays parallelwto the aXis X--X of the reflector A.
The third series of rays is marked g. This series of rays comprises only a very small proportion of the total light treated. These rays are direct rays and pass through the double concave lens b, being refracted thereby into a widely divergent cone 9 9. This light is small in amount to begin with and as it is spread over such a wide angle it 1s rendered so feeble that it is not productive 110 of glare.
Iilig. 2, shows still another series of rays which I:have marked g; these are direct' rays and pass through a plain glass b2, Without changing their direction to provide illumination of the road immediately7 in front of the head light.
I prefer to mold my double lens of one piece of glass, though this is not absolutely necessary. 4
Having provided means to eiiect the practical individual treatment of the direct. and reflected beams, whatI Wish to claim and secure by Letters Patent are:
1. In a headlight, the combination of an ellipticalreflector, a source of light located substantially at the inner focus of the reflector, a lens covering the mouth of the reflector and located near the outer focus of the reflector, said lens having a central concave`portion which receives all the reflected rays and issues them Vin a parallel beam of light and a plurality of arcuate concentric prisms which receive the greater portion ot' direct rays and transmit them in a parallel cylindrical beam of light.
2. In a headlight, the combination of an elliptical reflector in which the outer portion of said reflector is covered with a nonreflectino coating, a source of light located substantially at the inner focus of the re.- flector, a lens covering the mouth of the re- Hector and located near the outer focus of the reflector, said lens having a central concave portion which receives all the reflected rays and issues them in a parallel beam of light and a plurality of arcuate concentric prisms which receive the greater portion ot direct rays and transmit them in a parallel cylindrical beam of light.
3. In a headlights the combination of an elliptical reflector, a source of light located substantially at the inner focus of the reflector, a lens covering the mouth of the reflector and located near the outer focus ot' the reflector, said lens having a central double concave portion which receives all the reflected rays and issues them in a parallel beam of light and also receives the central direct rays .and spreads them laterally, and a plurality ot' arcuate concentric prisms Which receive the greater portion of direct rays and transmit them in a parallel cylindrical beam of light.
4. In a headlight, the combination of an elliptical reflector, a source of light located substantially at the inner focus of the reflector, a lens covering the mouth of the relector and located near the outer focus, said lens comprising a central double concaveportion, a plurality of arcuate prisms surrounding the concave portion and covering the u per half of the lens, the lower portion o the lens surrounding the concave portion being free from prisms and allowing a portion of the downward direct rays to pass unmodified.
n testimony that I claim the foregoing as my own, I aflix my signature.
JOHN A. RITTER.