US1560793A - Headlight lens - Google Patents

Description

' 1,560,793 J. M. DUNLEA y 'I HEADLIGHT LENS Filed Aug. 13, 1923 Hull i www;

Patented Nov. 10, 1925.

PATENT OFFICE.

, vJOHN M. DUNLEA, LOS ANGELES, CALIFORNIA.

HEADLIG'HT LENS.

Application led August 13, 1923. Serial N0. 657,058. f

To all whom. t may concern.'

Be it known that I, JOHN M. DUNLEA, a

. citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented certain new and useful Improvements in Headlight Lenses, of which the following is a specilication.

My invention relates to lenses of the type generally used on the headlights of motor vehicles and the principal objects of my invention are, to provide la lens of relatively simple structure, that will be effective in bending or refractin light rays that tend to travel upwardly rom the headlight of a motor vehicle or the like, downwardly into a predetermined horizontall plane or level, thereby efectually preventlng bright and glaring rays from being thrown into the eyes of the drivers of approaching vehicles, and also, to concentrate the' light rays that emanate from a headlight into V a relatively narrow horizontal zone, that covers the area most desired, viz, the roadway for a reasonable, or Vat the required distance directly in front of ,the equipped vehicle. `With the foregoing and other objects in view, my invention consists in certain novel features of construction and arrangement of parts that will be hereinafter more fully described and claimed and illustrated in the accompanying drawings in which;

Fig. 1 is a vertical section taken through the center of a lens constructed in accordance with my invention and showing same associated with a vrefiector and source of light. 0 ,v

Fig. 2 is an elevational View looking against the inner face of the lens.

Fig..3 is'an enlarged sectiontaken on the line 3-3 of Fig. 2. f

Fig. 4 is a vertical section through the center of a modified form of the lens.` i

Fig. 5 is a vertical section through the center of a further modified form of the lens.

' Fig. 6 isa vertical section taken through the center of a third modification.

Fig. 7 is a diagrammatic View showing the projection of light rays from one form of my improved lens.

Referring by numerals to the accompanying drawings and vparticularly to the form of lens illustrated in Figs. l, 2 and 3, 10 designates the disc-like body of the lens that is .in front of a conventional form-of parabolic" reiiector 1l and there being a suitable, source of light, prelerably an incandescent electric lamp 12 arranged within said reflector. y

The outer face 13 of the lens is flat and smooth, while the inner face, or the face that is adjacent to the source of light, is formed with a plurality of inclined faces that are arranged andV disposed so as to provide aplurality of horizontally -disposed prisms, the same being divided into two sets with one set located above the horizontal medial line of said lens and the other set below said medial line.

In'Figs. 1 and 2 I have shown each setv as comprising two prisms, and while this number is ample and vconvenient for all practical purposes, it is obvious that the number of prisms in each set may be increased orv diminished, as desired..v

In the particular construction illustrated in Fig. 1, the lower prism A. of the upper set, or that prism directly above the horizontal medial line of the lens is formed with its inner or rear face 14 disposed at a slight angle relative to a vertical plane, or the plane occupied by the outer face 13.

The upper prism B of the upper set, or the prism that constitutes the upper portion of the upper half:7 of the lens body, has its rear or inner face -15 inclined to a slightly greater degree than the inclination of the rear face ot lens A, so that when viewed against the side edge of the lens, the upper half gradually increases in thickness toward the top, and with the rear or inner face of the upper portion ofvsaid upper half, in-

clined to-a slightly greater degree than the corresponding face of the lower portion of said upper hall The lower half of the lens body is made up of prismsC and D that are very similar in vertical section,` or looking to the prisms A and B respectively, but said `prisms C and D are reversely. or oppositely arranged with respect to Said prisms A and B and, the angularity of thel two llower prisms, is slightly greater than the angularity of the corresponding faces of the upper prisms. Thus the light rays passing through and emerging from the lower prisms are bent or refracted to a slightly greater degree than the raysv that pass through the upper prisms.

Thus the relatively narrow upper edge of prism C unites with the narrow lower `edge of prism A, at the horizontal medial line of the lens body and the relatively narrow upper edge of the lower prism D joins the `relatively wide lower edge of vprism C.

.Thus the lower half of the lens body gradually increases in thickness toward its lower 4edge and with the inner face 16 of the lower prism D occupying'a slightly greater angle relative to a vertical planel or the plane occupied by the outer face 13 of said lens body, than the inner face 1T of prism C.

Where this form of lens is used in connection with a reflector and source of light that is focused to produce converging rays, the reflected rays in passingthrough the upper half of the lens or that portion embodying the prisms A, B, will be refracted or bent upwardly in the vertical plane, while the reflected rays in passing through the lower half or through prisms C, D, willbe bent or refracted downwardly in the vertical plane, but to a relatively less angular degree than angularity of the rays emerging from the upper half of the lens.

Thus my improved lens materially lessens the vertical angle between the rays emanating from the upper and lower halves of the reflector and, as a result, the zone or area of light is flattened or reduced in vertical dimensions. At the same time the light rays are concentrated and directed in a general downward direction, so that they are kept within a horizontalplane below the plane where the would otherwise strike the eyes of pedestrians or the drivers of approaching vehicles.

This lowering and concentration of the light rays throws the volume of li ht where it is most needed viz, for a few eet above 'and upon the roadway for a considerable,

or the legal-ly required distance in front of the equipped vehicle.

Fig. 7 illustrates graphically thev control of headlight rays with a lens of my improved construction and it will be seen that the rays emanating from the upper half of the lens and which rays are raised bythe prisms A, B, intersect the rays emanating from the lower half of the lens or the prisms C, D, at a point a considerable distance away from the headlight and in a lane below the center line or axis m--z of t e reflector and source of light. y

Thus my'improved lens materially lessens the vertical angle between the rays reflected from the upper and lower halves of the re- Hector and concentrated volume of light is maintained in a relatively low horizontal plane where it is most needed.

minating the side portions of the street or roadway that is being traversed by the equipped vehicle.

These ribs or grooves are preferably placed on the same side of the lens with the angular faces of the prisms as such arrangement leaves the outer face of the lens, when in service, smooth, and capable of being easily kept clean.

In the modified construction illustrated in Fig. 4, the lower half only of the lens is formed with the horizontally arranged prisms D and C as contemplated by my invention and, where this construction is employed, the rays of light passing through the upper half of the lens are not bent or refracted vertically, while the rays passing through the lower half, are refracted or bent downwardly.

The modification illustrated in Fig. 5 and which `embodies a practically reverse arrangement of the prisms from the arrangement' illustrated in Fig. 1, is designed for refracting and decreasing the vertical angularity of rays that diverge from a reflector.

Thus the rays passing through the upper half of the lens are retracted or bent downwardly and the rays passin through the lower half of said lens are re racted or bent upwardly.

In the construction illustrated in Fig. 6, one half' of the entire lens is of prismatic formation as designated b D, thereby revfracting or bending the lig t rays vupwardly or downwardly, depending, of course, upon the arrangement of the prism portion of the lens at the top or at the bottom.

Thus it will be seen that I have provided relatively simple, practical and effective means for refractlng or bending the rays of light that travel in an upward direction from a headlight or the like, down to a predetermined level and concentrating said light rays into the desired zone or area. Obviously the specific forins of the lens herein shown and described may be modified in various details, without departing from the spirit of my invention, the scope of which is set forth in the appended claims.

I claim:

1 A headlight lens having a front pla-ne surface, a rear surface comprising two groups of horizontal prisms, the lower group being disposed with their bases downwardly and having progressive refractive power downwardly, the upper group `being disposed with their bases upwardly and havin progressive refractive power upwardly an vertically disposed cylindrical prisms on said rear surface.

2. A headlight lens having a front plane surface, a rear surface having 'a horizontal prism located wholly below thehorizontal center of the lens body and extendin entirely across the latter with the base o said prism lowermost so that said rism has refractive power downwardly, sai rear surface also having a horizontally disposed prism located Wholly above the horizontal center of the lens body and extending entirely across the latter with its base uppermost, so as to have refractive power upwardly and vertical cylindrical prisms on said rear surface.

In testimony whereof I alix my signature.

JOHN M. DUNLEA.

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