US1419482A

US1419482A - Headlight

Info

Publication number: US1419482A
Application number: US356486A
Authority: US
Inventors: William G Wood
Original assignee: BERKELEY LIGHT CORP
Current assignee: BERKELEY LIGHT Corp
Priority date: 1920-02-05
Filing date: 1920-02-05
Publication date: 1922-06-13
Anticipated expiration: 1939-06-13

Description

W. G. WOOD.

HEADLIGHT.

APPLxcATloN FILED FEB.5,1920.

Patented lune EL3, i922.

a SSHEETS-SHEET l. F 5.,

lAlQQN Wmm @c Wam W. G. WOOD.

HEADLIGHT.

APPLICATION FILED FEB.5.1920.

Patented June EL3, 1922.

LQMQASQ.

3 SHEETS-SHEET 2.

W. G. WOOD.

HEADLIGHT.

APPLICATloN man FEB.5.1920.

94ML @Agg Patented Juno 13. 1922.

3 SHEETS-SHEET 3.

f-- INVENTOR WMM/m @.1 www unTTan sTaTas PATENT cierres.

WILLIAM Gr. WOI), 0F SAN FRANCISCG, CALIFORNIA, ASSIGNOR T0 IIBERKLEY LIGHT CURPOTION, @F ARSON CITY; NIETVAIJA,` A CGRIORATION 0F NEVADA.`

armament'.

To all wlwmz't may concern: 7 Y

Beit known that WILLIAM G. Woon, a citizen of the United States, residing at San Francisco,in the county of San Francisco and State of California, has invented new and useful Improvements in Headlights, of which the following is a specification.

This invention relates to projectors, and

the present application is in the nature of a 1 contlnuation in part of my prior application, Serial No. 209,833, led January 2, 1918, and entitled Reilectorf rllhe object of the invention is to produce a light field, especially suited for automobile headlights, wherein the light rays of greater intensity illuminate that part of the roadway farthest from the car and the light rays of lesser intensity illuminate. that part of the roadway nearest the car. rllhat is the reverse of ordinary headlight illumination and is the ideal system for automobile headlights. I accomplish this object by using any one of several diderent arrangements of reflectors and lenses, some of which are exemplified in the following description and illustrated in the accompanying drawings, in which :-4

a vertical central sectional Fig. 1 show dlight and casing embodying view of a hea my invention.

Fig. 2 shows a dia ram'in vertical section of the composite re ector employed inA my Y device and illustrating one form thereof.

ri 5. Y f Fig. 7 shows a dlagram 'in elevatlon of a Fig. 3 shows a plan view of the arrangement shown in Fig. 2.\

- Fig. 4 shows a front elevation df the light emitting aperture -in the front of the casing. Fig. 5 shows a diagram in elevation of the composite reflector and the beam projected thereby.

F ig. 6 shows a diagramA of the light field produced by the arrangement shown in modified form of composite reflector, wherein the reflector produces a slightly dier'ent form of beam from that shown in Fig. 5.

specican'onofreae1-sPatent. Pmqmmdi Jun@ 13, 1922:, Application led February 5, 1920. Serial No. 359,486.

Sshows a plan view of the arrange- A in detail to the accompanying.

l OOD-jtaimng a source of light 11 in the bottom parallelism and strike a second reflector 13 inthe upper part of the housing, ysaid second' reector being a composite reflector, one part A of which is preferablya portion of a conical' reflector and the other part Bof which'isV a portion of a paraboloid, sphere or other concave reflector. The reflector 13 is a surface generated' by revolving a parabolic arc, or other curve Z) and a tangent a at one extremity thereof, about an axis C parallel to the incident rays. In any instance, the part of the surfacegenerated by the tangent will be in the nature of a section of.

a cone. W hen the `axis of the parabolic arc is co-incident with the axis of revolution the surface of thereflector portion B is that of a section of a paraboloid, and the portion A is a section of the surface of'ya cone which is tangent 'to' the surface ofthe paraboloid at the circle of junction, Figs. 1, 2 and 3. When the axis D of thev parabolic arc is not coincident with the axis of revolution, as in Figs. 7 and 9, then the reflector portion B becomes such as to have two lines where the rays cross, one in a vertical plane, indicated at 17 and another in a horizontal plane in` lens 15 it will be noted is parallel with the -v coincide with the vertical focal plane of all rays projected by the composite reflector 13.

The character of the beam projected by the reflector part 'A is wedge-shaped,- the rays F projected thereby being parallel 1n a vertical plane and crossing within the aperture 14: and diverging'in a horizontal plane as they pass therefrom. These'rays F are preferably. horizontal or i'ncllned downwardly, land consequently continue out a great distance. When projected.- upon a screen or wall at a distance from the lamp,

the field produced thereby corresponds to the portion marked X in Fig. 6. The character ofthe beam projected by the reflector portion B is' such that the -raysCr converge in all'planes, crossing each other andA continuin'g out divergent in all planes. The\ eld thereof is indicated at 0 in Fig. 6.

By having the rays yfrom both reflector arts A and B cross within the aperture-14C', am enabled considerably. to reducel the y width of said aperture and thus prevent any substantial portion of the light source or reflectors from being seen by an observer stationed in front of the lamp. ln so concealing.

the light source and reflecting surfaces, much;

4of the glare that is present in ordinary headlightsis eliminated. Also this reduced light emitting aperture has the further advantage of cutting out stray and vagrant rays which,

if allowed to pass through, would 'cause more4 or less spreading and. diffusiono-f the light and prevent the formation'of al beam of sharp outline such as is characteristic of the present lamp.

By locatin the horizontal crossing line for the rays back of the lens 15, as shown in Fig. 9, l am enabled to employ a baffle or diaphragm 19 positioned as shown in Fig.- 9 to cut the uppermost rays from the reflector portions A and B sharply and clearly. This is best attained by locating the baffle 19 a distance to the rear of the lens 15 corresponding to the focal length of said lens.

t is important in the construction of a headlight that the rays forming the upper portion of the beam be horizontal or inclined downwardly in order that the light may not be thrown into the eyes of an operator ofan approaching vehicle and also to insure that such rays will serve to illuminate the part of the roadway nearestthe car. On the other hand, the rays F of the wedgeshaped beam projected by the reflector part A should be horizontal or slightly below in order that they may continue out and illuminate objects farthest from the car since such rays F are of greater intensity than the rays G. The reason for the greater intensity of the rays F is to be found in the fact that they are reflected from a considerable poronly in one plane they lose little of their ininmates tensity even at a considerable distance from the lamp. 'On the other hand, the raysfnr will have less'intensity owing to the fact that they diverge in all planes and there is not the concentration that is to be found i-n the case of the rays F. Moreover, aapart of' the rays from the upper portion of the reflector 13 combine with they rays from the lower portion... Hence, vthe intensity of the part X of the field is reinforced and'strengthened thereby.

all planes and hence illuminate alarger field,

including a considerable area beneath that portion of the field of-increased intensity.

Other forms of reflectors 13 suitable for accomplishing my objects may be produced by revolving either a straight or curved (regular or irregular) line, or'any combina-v tion of these, about- `an axis which is parallel to the incident rays. A

-The various modifications shown in Figs. 7 Vto 11 inclusive embody the same combination of parts as shown and described in the precedin figures, except that the composite reflector 1s differently shaped. In all cases the composite reflector is formed by revolving a curved line b and a tangent a at one extremity thereofl about an axis C, which axis is parallel with the incident rays. C in every instance coincides with the position of the light emitting aperture in the housing. This method of forming the horizontal curvature of the composite reflector will insure a. common vertical crossing line at C for all of the rays. rThe rays reflected by the portionb may also cross each other on a horizontal line at other points on positions which will be determined by the 'curvature of the line b. ln Fig. 7 et. seq., the curvature of b is such as to cause the -rays to cross again at 18. In all of the figures l show the axis C the same distance from the reflector, but in Figs. 7 and 8 the crossin points or line 18 is in front of the axis whereas in Figs. 9, 10 and 11 these points 18 are behind the axis C, from which it follows that the curvature of the reflector portieri B in a vertical plane is less inthe case of Figs. 7 and 8 than in the case of Figs. 9, l() and 11. The purpose of these modifications is to show that the beam projected by the cornpositereflector may have a plurality of focal planes or crossing lines differently posi@ This axis intensa tioned and also to demonstrate as in the case of Figs. 9, 10,-and 11 the use of a screen or baflier member 19 arranged within the hous` ing at the required distance from the objective lens 15. Y

Having thus described my invention, what l claim and desire to secure by Letters Patent is:

1. A headlight for vehicles comprising a housing, a source of light in the housing, means to project parallel rays therefrom vand a composite redactor to receive the parallel rays` and having, means to project them out from the housm -in `the form of a beam having downward y' inclined rays diverging in a plurality of planes to illuminate objects nearest to the vehicle, said reflector also having means to project rays substantially horizontally and diverging in one plane only whereby to illuminate objects a greater distance from the vehicle.

2. ln a projector, a composite vreflector having a portion provided with 'means to reflect parallel incident rays so as 'to converge them in one plane and another portion to reflect parallel incident rays soas to converge themfin a plurality of planes, all

of said rays crossing on a straight line, and means to project parallel light rays against the composite reflector.

3. A. lamp comprising a housing having a narrow vertical'li ht emitting aperture, a source of light wit in the housing, means to project parallel rays from the source of light, and a composite reflector 'within' the housingvto receive the parallel rays, said compbsite reflector having one portion provided with means to reflect the rays so as to converge in one plane and another portion to reflect the, rays so as to converge in different planes, all of Said rays crossing within the narrow light emitting aperture'.

A. A lamp comprislng a source of'light, means to project parallel V rays therefrom and ay composite reflector' to receive the parallel rays, said composite reflector hav, ing 'a lportion provided with means toproject a wedge-shaped beam, 'and another portion provided with means to project a conic-al beam.

5; A lamp comprisinga source of light, means to project parallel rays therefrom, and a composite reflector to receive the` parallel rays, said composite reflector having a portion provided with means to project a wedge-shaped beam and another portion provided with means to project a conidal beam, the parts of said reector being so arranged that the rays of the wedgeshaped beam are substantially horizontal and the rays of the conical beam are inclined downwardly.

.6. A lamp comprising a housing having a narrow vertical light emitting aperture in the front thereof, an objective lens for a narrow vertical light emitting aperture in the front thereof, an objective lens for said light emitting aperture, a source of light inthe housing, and means co-operating'` with the source of light to project a convergent beam through the narrow aperture, said means comprising a reflector shaped to produce a field of li ht having a band at its upper portion o comparativelyv great intensity and a curved lower portion of less intensity, and means in focus with the objective lens to cut the (upper border of the beam sharply.

curved lower 8. lin a projector, means to produce" lparallel light rays, a composite reflector to receive said parallel rays having one 'portion in the form of a section of a cone and another portion in the form of a section of a concave figure, both of said portions having their principal axes parallel to each other and to the incident rays,

9. ln a projector, means to produce parallel light rays, and a reflector to re- `i ceive the parallel rays, said reflector having a surface generated by revolving a parabolic arc about an axis eccentrically located withv respect to the axis of said arc and parallel thereto.

.10. lln'a projector, means for producing parallel light rays and a redector to receive said parallel rays, said redector havn ing a surface are of a curved ody, the axis of revolution of which is parallel to the incident rays and eccentrically located with respect tothe axis of the concave body.

11. lln a projector, means to produce parallel light rays and a reflector to receiaef said parallel rays, said reflector having a. surface generated by revolving a curved line and a tangent at one extremity thereof about an axis parallel to the incident rays.

12rln a projector, means for producing parallel light rays and a reflector to receive the parallel rays, said redector having a surface generated by revolving a parabolic arc and a tangent at one extremity thereof about an axis eccentric Lwith the axis of the parabolic arc and parallel thereto. 13. ln a lamp, means to produce parallel light rays, a unitary reflector having a por=- tion shaped so as to reflect parallel incident rays convergently inv one plane and another portion shaped to reflect parallel incident rays convergingly in all planes, all

enerated by revolving an of said rays crossingon a straight, line and continuing out dvergently.

14. ln a projector, means to reflectK parallel incident rays convergently in one plane and means to reflect parallel incixent rays convergently in a plurality of planes,

.all of said rays crossing on' .a Vertical line, and continuing out, divergently.

15. ln a projeetor, means to produce parallell light rays, means to reiect parallel.

Mieeea tinuingI out' divergent1y, said reflecting meansbeing so arranged as to cause the rays which diverge in one plane to illumiv nate the upper portion of the ield, and those which diverge in a plurality'of planes to illuminate the same portion of the field and a considerable area beneath.

ln testimony whereof l have hereunto set my hand in the presence of two subscribing Witnesses.

. .WILLAM G. WOOD. Witnessesz' VALERIE DE REMERa JOHN H; Ne..