US1216910A - Projection apparatus. - Google Patents

Description

A. AMES, In. PROJ ECTION APPARATUS.

APPLICATION FILED JUNE 6.19MB. 1,216,910. Patented Feb. 20,1917. 3 SHEETS-SHEET I.

e jv'q. 2

\ A. AMES, JR. PROJ ECTION APPARATUS.

' APPucmofl FILED JUNE s, 1916. 1,216,910. Patented Feb. 20,1917.

3 SHEETS-SHEET 2.

A. AMES, Jn. PROJECTION APPARATUS. APPLICATION FILED JUNE 6. 1915.

1,216,910. A A Patented Feb. 20,1917.

3 SHEETS-SHEET 3L :ilf a '45 dal' surface substantially coincides with the paraboloidal surface, with thethe ellipsoidal surface lying in front ofthe common focus, and position by ing the light source to the rear ofthe com-. ,mon focusN'With this arran 'ment the light reflected from the paraboloi al,- surface may" To all whom it may concern UNITED FF CE;

annnnnn'r m, or rnwx'snunr, naesacnusn'r'rs.

Be it knownthat I, AnELBi-m'r Anne J r., a citizen of the United States, and resident of Tewksburv, in the county of Middlesex and .State of Massachusetts, have invented new and useful Improvements in Projection paratus, of which the following is a spool vention relates to a hea ight for u I 'without producing .upward glare, that is,

cation. 7 This invention relates to light projection apparatus designed toproject a sharply defined, concentrated beam of li ht a consid-' More articu arly the inon automobiles and the like adapted to i uminate the roadway far in advance of the vehicle erable distance.

' without projecting substantially any light a above a horizontal plane pasein through the regionof the light source, an at the same time adaptedto produce distributed illumination for relatively short 'and intermediate .distances along the roadwia In my prior application rial No. 72,503, filed January 17, 1916, I havedisclosed light projection apparatus having'a reflector comtwo or more surfaces each havi a contour generated bythe artia-l revolution of aconic section. Suitab e contours of this character comprise for example,'paraboloids and ellipsoids. Sultablearrangements of a plurality of such surfaces com rise, forexample, ajparaboloidal surface orming subi an ellipsoidal surface forming substantially,

the upper half of the reflector, or aparaboloidal surface forming substantially each half of the reflector, the light source being. in the region of the plane dividing the two surfocus of the faces. l

rhalf of the reflector and a parabfer likaifuple, mostof the upward glare may be eliminated by'so arranging the two sur faccsjthat one of thetwo foci of the ellipsoiother focus 0 be projected in and below a horizontal direction while thelight reflectedfrom the ellipsoidal'surface may beprojected downwardly-and in the general direction of the axes of the reflector surfaces are dal surface for the lower hal 'tor and an elli soidal surface for the upper surface for the lower half thereoffto eliminate upw the class descri raomc'non APPARATUS.-

anna dream latent. Patented Feb. 20, 1917, Application ma 1mg, 1010., Serial no. 102,053.

second focus of the ellipsoid. Other arowe'ver, in nearly all cases where the" I itioned substantially horizontally to aflor a conoentrated' beam oflight which can be projected a considerabledista-nce along the roadwa fpqo some light is projected in 'an upward direction. This I have found to be due to the fact that, inasmuchas all'light sources have appreciable dimensions, parts of the light source are necessarily displaced relatively tothe foci of the reflecting surfaces andrclatively ,to the substantially horizontal plane containing the axis of one or both of the refleeting surfaces. The major portionof the glare due to this fact can be avoided by pro erly positionin tive y to the foci o? the re For example, when employing a paraboloiof the reflechalf thereof, with the rear focus of the e s'oidal surface coincident with the focus of the paraboloidalsurface,.most of the upward glare can be avoided by positionin the light source behind the, common foci. T e remaining glare can be eliminated by shifting the light source upwardly as well as rearwardly,

, so that it lies behind and above the focus of stantially the lower half of the reflector and" the' paraboloidal surface as hereinafter explained. 1 V

, However, for some purposes it is desirable to keep the light source in the axis of the f reflector, particularly in the case of a pawl 'oloidal reflector as, for example, for the purpose of maintaining strong concentration of light in an axial direction.

the-1i ht source relaecting surfaces.

The principal object .of this invention is ard glare in headlights of ed un er the above and similarjcircumstances, and at'the same'ti-me to utilize all or substantially all of the reflectsurfaces to project a concentrated beam of light in substantially an'axial direction, {whereby a beamof light sharplly defined I ahorizontal planepassing t rough the high of. concentration in an axial direction may be produced."

v -Inthe accompanying drawings which are largely diagrammatic,

I Figur'elshowsone embodiment of my in vention, whereina of frosted glass'is of the light "source and having a employed on the horizontal, central portion of the glass cover;

Fig. 2 is a front view of the apparatu illustrated in Fig. 1;

Fig. 3 shows another embodiment of my invention in which a non-reflecting band is provided on the reflector surfaces adjacent a horizontal plane through the region of the light source;

Fig. 4 is another embodiment of the invention showing a prism positioned in front of the light source;

tus shown in Fig. 7; a

Fig. 9 is an embodiment of my invention in which the upper reflectingsurface is extended below a horizontal plane passing through the light source;

Fig. 10 is a front view of Fig. 9;

Fig. 11 shows a further modification of this invention. in which the lower reflecting surface is extended above the said horizontal plane; and

Fig. 12 is a front View of Fig. 11. In the embodiments of the invention shown in Figs. 1 to 10 inclusive, the portion 'F of the reflectorabove the horizontal plane.

passing through-the region .of the light source comprises an ellipsoidal surface, while the portion F of the reflector below the said horizontal plane comprises aparaboloidal surface. \Vith one of the foci f at this point, in this type of reflector, all the be projected in an axial direction, and all would pass through the second focus of the ellipsoidal surface and be distributed along the roadway in front of the headlight. However, owing to the fact that all light sources have appreciable dimensions, some of theparts of the source must of necessity I be displaced relativelyio the'foci of the The following brief reflecting surfaces. outline will indicate the effect of the displacement of the light source in the various directions from the focus of a paraboloidal surface.

If a point source of light is displaced in a forward axial direction, in a paraboloidal reflector, the light issuing therefrom will'be Fig. 5 is another embodiment of the inven- Fig. 8 is a front elevation of the apparaof the ellipsoidal surface and the focus f. of the paraboloidal surface at the same point and with a point sourceof light positioned light reflected from the lower surface would the light reflected from the upper surface reflected toward the axis, and with the refleeting surface below a horizontal plane: containing the axis, as illustrated in the drawings, the light will be radiated in an upward direction. In Fig. 1, for example, a ray of light 1 radiating from a point 2 axially displaced in front of the focus f of the paraboloidal reflector F and striking the reflector at 3, would be reflected in an upward direction as indicated; Any ray issuing from the focus will be reflected horizontally, as illustrated for example, by rays 4: and 5. A ray of light emanating from a point in the axis of the reflector behind the focus thereof will be reflected in a direction diverging from the axis and therefore ina downward direction. In Fig. 1 for example, a ray 6 issuing from the rear point of the filament L and striking the reflector at point 8 will be reflected downwardly as indicated. A ray issuing in a plane contain ing the axis of thereflectorfrom a. point displaced from the axis will be reflected inwardly or outwardly, and therefore upwardly or downwardly with the reflecting surface below 'the axis thereof, depending upon whet-her or not the path of the ra in-.

tersects the axis in front of the focus. hus, the path of the ray 11 issuing in the plane of the paper from point 12 and strikin the reflector at 13 intersects the axis behin the focus and is' reflected outwardly and downwardly.

In the preceding paragraph only rays in planes including the axis of the reflector were considered, that is, only the effect of the paraboloidal curvature of the reflector was considered. A paraboloidal' reflector may also be considered as being made up of a plurality of circular elements lying respectively, in planes perpendicular to the axis. Upward glare also results from axial displacement of points of the light source owing to this circular curvature;

Considering points of light 21, 22 and 23 in Fig. 12-, for example, which are radially displacedfrom the focus f in a plane perpendicular to the axis of the paraboloidal surface and containin the focus and the circular element 24, an considerin only the effect of the circular curvature o the surface upon the rays of light issuing from the said points. in the said plane, the angles which the incident rays make with the radii of the circular element will be equal, res ectively, to the angles which the correspon ing reflected rays make with the radii. Thus, the incident and reflected rays 25 make equal angles a with the radius 30. The same is I true of rays 26, 27, 28 and 29, and, if affected only by the circular curvature of the reflector these rays would be reflected as indicated by the dash lines 25 to 29. I

However, due to the combined circular and parabolic curvature, the rays 25 to 29 4 fcolnponent tangential 'to the circular e ewould be reflected forwardl from the reflector, out of the vertical p ane containing the focus, the points 21 to 23, and the circular element 24 of the reflector, and the actual directions taken by these rays would be such that the projection of the rays upon the said vertical plane would be as indicated a at 35, 36, 37, 38 and 39, respectively, as will be apparent from the following considerations. I

A plane tangent to any point in the circular element 24 of the paraboloidal reflector would. make an angle of 45 with a line drawn from the focus to the said point,

In Fig. 11, for example, a plane represented by the dash line 19, tangent to the reflector at point 20, makes an angle of 45 .with the'line connecting the point and thefocus.

A ray of light emanating from the focus and incident to the reflector at point 20 would be reflected in a horizontal direction and the projection of the reflected ray on a plane perpendicular to the axis of the reflector, as for example, the plane upofi the normal .to 29 .due in the displacement of the light' of the paper in-Fig. 12, would appear as a point. The same is obviously true of all rays issuing from the focus and incident to the reflector on the element 24. Now the resultof moving the light source from the focus in the 'saidvertical plane is to deflect the reflected ray in a direction havinga component tangential-to the element 24 and the amount of tangential deflection depends istance from the focus to the path ofpthe ray. Thus the dash lines 35 to 39' roughly indicate the relative tangential deflection of the respective rays 25 source points 21 to 23. Each of these reflectedrays may have a direction havin a' j -ment.

n will be, noted that all incident rays 1 ing in ines crossing the vertical plane con-.

taming the axis above the axis, such as, rays 25 and 26, are deflected'downwardly and that all incident Trays lying inlines crossing the said'vertical planebelow the axis, such as rays 27, 28 and 29, are deflected upwardly. And while I have only shown rays in the transverse plane through the focus of the reflector for the purpose of illustrating the effect of, radial displacement 'of points of thelight source, it will be a parent that radial displacement will pro .uce similar eflects on rays emanating in planes behind and in front of the focus and also upon rays which emanate at angles to planes perpendicular to the axis.

Thus, due to circular curvature, displacementof points of the light source above the horizontal plane of'the axis of the parabolic surface tends to cause downward deflection of the reflected rays, displacement of points of the light source below the horizontal the focus. p

flectorabove point 10 are projected slightly above the horlzontal direction as illustrated plane tends to cause an upward deflection of the reflected rays, and lateral displacement tends tocause upward or downward deflec tion depending on whether the pathsof the 'raysextend below or above the axis. And,

due to paraboloidal curvature, displacement of the light source to the rear of the focus tends tocause outward, and consequently downward deflection where the paraboloidal surface is below the axis thereof, while for ward displacement of the source ,tends to cause inward and hence upward deflection.

At any point intermediate the axis and .the plane-through the focus perpendicular to the axis the effects of the circular and paraboloidal curvatures vact either cumulatively or differentially depending upon the direction of the point from the focus and.

depending, uponthe-direction of radiation of the particular ray'r Considering four zones produced by a horizontal plane containing the axis and a vertical plane through the focus perpen dicular to the axis, itcan be said, in general,

that raysemanating from points in the rear, upper .zonewill. be reflected downwardly and horizontally inasmuch as rearward displacement tends. to produce downwarddeflection due to the parabolic curvature, and upward displacement tends to "produce downward deflection due principally to the.

circular curvature. Hence, in the embodiments of my invention illustrated in'Figs.

6 and 7, where the light sourceis positioned in the said rear, up er zone, no upward glare would result. he source may,-if desired, be so placed in any or all'of the otherr embodiments. As above stated, however it is at times desirable to kee source in the axis of the para oloidal 'refleeting surface and in Figs. 1 to 5 and Figs. 9. and 10, I have shown the light source in the axis to the'rear of the focus. l

The ordinary commercial light source em-. I 1

.ployed inheadlights comprises either aV the light "105 shaped filament substantially as illustrated in the drawings or a helical filamentffi'Thus parts of the .fi

placed relatively to the axis.

ment placed behind the focus of the paraboloidal reflector, as shown for example in Fig. 1, all rays radiating rearwardly and striking the reflector at a point below point ament necessaril will be dis ith the fila- '10 will be projected in or below a horizontal direction owing to the fact that all such rays appear to come from points behind However, rays striking the re by rays 1 and 4, for the reasons above set forth. Some means, therefore, is required to prevent upward lare due to the rays incident to the para oloidal surface in the rear of the light source.

Upward glare is not caused solely by that ao .axis to a maximum at region of the reflector in the rear of the light source, but also is caused to some eitent by the side portions of the reflector adjacent the horizontal plane through the light source. This source of glare is due; principally to vertical displacement of points of the light source relative to the aforesaid horizontal plane and to the circular curvature of the reflector as will now ap ear. 1 eferring again to Fig. 12, which illus-v trates the efiect of the circular curvature of the reflector, itwill be noted that the upward (or. downward) tendency of the horizontal components of the reflected rays increases from a minimum below the points adjacent the horizontal plane containing the axis of the reflector. hus, due to vertical displacement of points relative to the plane, upward glare is most likel to result from portions of the reflector adjacent the said horizontal plane.

Furthermore, the tendency to deflect the rays downwardly due to the parabolic curve ture produced by shifting the light source rearwardly, is a minimum in the case of rays radiated approximately horizontally andstriking the reflector adjacent the said hurl; zontal plane, shifting .the light source rearwardly of the focus. is toincrease the divergence of the rays from the 'axis;.and the downward component due to this increased divergence is a maximum below the axis and a minimum adjacent thehorizontal plane through the axis.

Thus, while tendency toward glare from the major portion of the lower reflector can be readily counteracted by shifting the light source rearwardly of the focus, it is necessary to provide special means to horizontal plane,

revent upward glare from the portions of t e reflector adjacent the aforesaid horizontal plane in order to Obtain a concentrated beam of 1i ht which can be pro'ected a considerable istance without pr ucmg upward glare.

Some upward glare is a so caused by the rays whic emanate iromcpoints of the light. source below the axis an which strike the upper half of the reflector F adjacent the as shown in Fig.4 by my 17 and, striking the 16 issuin from point reflector at 18.; This is ordinarily true revolution of a conic section.

. whether the uppcr'suriace be paraboloidal,

or or other contour formed by the However, when employing an ellisoidal surface for the upper half ot the re actor, Figs. 1 to 10, the tendency to reflect the re s ulwardly is limited to the a e. ipsoidal surface in immediate proximity ellipsoidal to the horizontal plane containing the axis .for the reasons above mentioned n connection with the portion of the lower reflecting for the efiect on allrays as shown in portion of t e.

surface adjacent the said horizontal plane, and for the furtherreason that an ellipsoidal s'urfacepositioned with both foci substantially in the said horizontal plane tends to project the rays reflected therefrom in a downward direction.v By my invention the upward glare due to the aforesaid causes may be avoided by employing any one of a number of specific means.

' In the embodiment of my invention shown in Figs. 1 and 2, the transparent cover G of the reflector is rendered translucent by means of a band of frosted glass FG across the horizontal central portion thereof. By this means all the rays which strike the two halves of the reflector adjacent the horizontal plane containing the axes of'the two surfaces and which would otherwise be reflected b -'I hus"therays incident to these portions of the reflecting surfaces which would other wise he reflected upwardly are absorbed by the non-reflecting surface.

In Fi 4 a prismP horizontally disposed across t e central portion of the reflector serves to deflect downwardly therays which are incident to the reflecting surfaces adja-- centthe-horizontal plane'and which are re flected-in a direction slightly above the horizontal. The rism islshown as being formed as an integra part of the glass cover G, but.

it maybe constructed and supported in any desired manner.

In the specific embodiment of my invention shown in Fig. 5, the curvature of each of the two halves of the reflector is modified adjacent the horizontal plane in sucha .man-

nor as to pro act the rays which emanate aproximately orizontally frompoints o'f thev i ht source dis laced below the horizontal 1182 Rue in or be ow a horizontal direction. is result can be accomplished by making a narrow portion M of t e-ellipsoidal surface adjacent the said horizontal plane tan- E elptial to the remaining ellipsoidal portion.

curvin 'the surface inwardly, as at M. suitab egeontour for the upper margin of the parcboloidalhalf of the reflector will be produced by giving the margm a curvature toric in character, having a'radius r, and a locus of centers on a line arallel to the paraboloid in a plane paral el to the horizontal axial plane and at distance oc therefrom.

paraboloidal half of the reflector may be modified adjacent the horizontal planebX i the two reflecting surfaces.

expedients herein illustrated would suffice if Two or more of the specific means for accomplishing the objects of my invention w-may be employed in a single projector. In

Fig. 6, for example, I have shownithe reflectors modified in curvature adjacent the horizontal plane as in Fig.5, a prism P as in Fig. 4, and the light source.L positioned above and behind the common focus f of to be understood that either one of the three j properly and accurately applied.

ln Fig's. 7. and 8 I have shown "the upper ellipsoidal. surfaceF reduced in size to such an extent that the centralelement thereof forms a smooth curve with the central element of the paraboloidal surface F. With this construction, the rear casin of the projector maybe made of parabo ic contour throughout i h the ellipsoidal reflectorcontained wholly within the casing. Further more, an auxiliarysource of lightAS maybe placed in the upper central portion of the rojectorfor: use where only a signal light is desired. The front portion of the projec-j tor surrounding the auxiliary source of light maiy be inclosed' by suitable means C foll'owin ed owing to the fact that the li ht source is this embodiment ofmy invention the p focusf of the paraboloidal surface is positioned above and in' front of the focus f of the ellipsoidal s'urfaceF, and the light source L is positioned between the two foc'i. This arrangement avoids upward glare for the reasons: With relation to the parabololdal surface, upward glare is avoidpositioned to the rear of the ocus f "and owing to the fact that the source is positionedabove the horizontal plane dividing the two reflecting surfaces. With relation to the ellipsoidal surface, upward glare is avoided owing to the fact that all ra s incident thereto emanate from points'in ront of the first focus 7 and therefore cross the horizontal plane behind the second focus of the ellipsoidal surface. Ordinarily, the secondfocus of the ellipsoidal surface would be positioned in the same horizontal 'lane with that of the first focus f, but in or er to roject the diverging beams of light forme by the ellipsoidal surface farther up the road- 1. way, the second focus may be positioned above the horizontal plane.

I have illustrated diagrammatically another embodiment of m invention 1n Figs 9 and 10, wherein the e lipsoidal reflector F is reduced in size as in Figs. 7 and 8, and extended below the horizontal plane passing through the region of the light source within the ellipsoidal reflectingsurface. The lower portion 42 of the upper half of the reflec'tor 1s made tangential to the remaining elli soidal ortion beginning a short distance a ove the horizontal plane,- as in Figs. 5 and 6. In this arrangement the rays which emanate However, it is mg surfaces lower surface is extended above the hori 9 having a from the portions of the light source below the horizontal plane containing'the common focus and which would otherwise be re flected in'an upward direction from'the portions of the reflecting surface adjacent to said horizontal plane will bedeflected downwardly by the eXtend U n- M e mp n y soidal surface.

Figs. 11 and .12 illustrate still another species of my invention, in; which the lower half of the reflector is extended above the horizontal plane through the region of the light source within the upper half of the reflector, and the upper portion 144 of; the

.loWer halfris modified as in Figs. 5 and 6 to prevent upward lare due to rays emanating substantially horlzontally frompoints of the light source displaced below thehorizont'al lane 'containin wing to the fact that the the axes of the two reflect d if.

zontal plane, the portion of the upper reflect- I ing surface adjacent-the said plane is shieldmodified in curvature as in Figs. '5 andfi g In i this species of-m invention I have shown both the lower re ector F and the upper re flector F" as of paraboloidal contour. 1

0 h. of the modifications of my inv ifl tion, the means provided on eitherflside ofthe horizontal plane through the light source should .in practice be extended for a some 3 ed fromthe light source and need not be what reater distance on either side ofthe said p ane than is theoretically necessary in. order to provide a safety-factor to takecare I of such variable factors as differences in sizes of commercial light sources and imper-" factions and inaccuracies in the shape and relative positions of the various parts of the projector. v

- Furthermore,

I. have found that .upward glare results'from portions of thexi-eflector i arther removed from the horizontal'plane through the light source in the region behind. the light source than in the other regions adjacent the s'aid horizontal 1 lane,

namely, the side re 'ons of the re ector.

For this reason I pre erably provide, for the region behind the light source, glare prev I venting means of additional width. For example, in Fig. 1a circle of frosted, glass FG',

reater diameter than the width of the ban of frosted glass FG, is rovided at the center of the glass cover; an in Fig. 3 semi-circles of non-reflecting surface NF,

having greater diameters than the width of a the two nonreflecting bands NF, is provided the skirt 42 extending below the horizontal plane of the light source has a lip 43 at the central portion of its lower edge; and, in

Figs. 11 and '12, the extension 44 has a lip back of the light source. In Figs. 9 andlO, I Y

at45 at the central portion of its upper edge. i However,instead of roviding wider glare I preventing means at t e central portion of plane res ectivelyyit is to be understood that 1 each of t ese surfaces ma form of a compound surace comprisin -a-- "plurality of segments each having a di er- I .20

has

the-headlight than at the sides the means may have the larger dimension throughout the entire width of the reflector. For example, in Figs. 4 and 6 the glass prisms P have vertical dimensions equal to the di-.

ameter of-thecircle of frosted glass FG. in and, in Figs. '5 and 6, the modified curvatures of the reflectors adjacent'the horizontal plane through the light source have substantially the same width throughout as the vertical dimension ofjthe non Whil'e ,Ifttvs' described-a single reflecting surface-"above and below the horizontal ent degree of curvature, as disclosed for example in m prior a plicatlon Serial N o.

. 72,503, filed anuary 1 1916,inthe event that'light distributlonotherthamthat ob.

age of.zlight ireflected backwardly headlightcover; increases with increase of y from about 5% at normal incidence to almost; 100% at grazing? incidence, an appreciable 'amo'unt of lightwould bereflected' from the portions of the cover adjacent the periphery thereof when employing m improved apparatus designed to project). "a am of light sharply definediat one side, 1 this reflected light is decidedly objectionable.

e In Fig. 4 Ihaveillustrated this'efiect by a ray reflected from the iflat glasslcover;

at 51 to the reflector F'- at po nt 52 andthence projected upwardly;' "I overcome this i (shaped an 'positione r sourceand to the p .a-glass cover the fl atj .dent thereto-at more nearly normalinci-H dence, resultin'glin less light bein tainab e by means-p single Waters-s is ,sirai.

Another feature. of my. -apparatus" com-'- prises a coverv for thef-projector arran "ed to revent. upward glare due to light being re ected from the rear face ofthe glass:

tive-locations and directions, and that my "invention is" not: limited to headlights em I ed-=solely in, the position herei'n' defront cover to the pro] wardly.v .Owing to the fact that the percentector ,and thence up the angle} of incidence.

an ordinary flat glass cover;

naive, to. thelight;

ample, I haveshown one form of farther orward so that the light. is ind-- reflected: therefrom. Furthermore, most 0 fFig; an form of non-g are headlight.

'light 1 is reflected. inwardly from the glass I bulb which-otherwise will strike the reflectsource disp be made'insthe a, istance equal'tothe rearward disp1ace-.

ment of the light.source. The light thus.v "reflected and ,-focused radiates from the .JPl- I scri edgjgOn thefco'ntrary,-the i'nventionis applicable wherever it-is' desiredto project i j if fa beam of; light sharply defined on at least 'from the horizontal direction a'concentrated' beam of paraboloidal reflector that. either no substantial amount of light wilt; r -be reflected from the said glass coverz-or .if a substantial amount is 'reflected',-"itwill not strike the reflector at such an angle as to be projected upwardly. In Fig. 5, for excover for; accomplishin he desired result comprising %r" having a cylindricalportion 1v 53 extending rearwardly therefrom. Thus I ortion of the cover ispositioned f;

Which is, reflected .will not strike. .thw'mi J'ector utwill pars-t o g cylindrical. f

portion 53'of the cover as shown in Fig. 5, ray '54 incident to the glass coverat-55. hile I- have only shown as ecialcover in. 5, it is to be understoo' that-git m preferabl should be used each In this particular ty ing surfaces at such angles as to be .projected upwardly. For example, with'the light aced behind the' center of the bulb the reflected light will focus at "a-point dis laced in front-of the center of the bulb focus point to the reflectors as from a. 1i ht orward displacement ofthe point forward displacement-above described.-

It 's'tofbe understood that the .wordshorizontal, vertica'hlupxward, downward, etc., are

"lused throughout t e sp'ecificationand claims merely for convenience in referring to rela- Q 1. Light projection apparatus.- comprising *a reflector, and alight source having at least- 1 two substantial dimensions, thercflector "be ing shaped and positioned with; relation to the lightsource to reflect .inand, 'below'a light sharply defined 'ojn'its upper side and to pro ec -substantiallyno light'upwardly. 2. Light projection apparatus" comprising .positioned"w1th relation to the focus sothat;

-' 3. Light projection apparatus comprising. v a: reflector adapted toproject 'a concentrated j substantially no ligh "beam of light-I-inandbelowa horizontal di- 7 rection, a' light 'fsourcehaving a substantial stantially" all]v rays 1;. if light? radiating "rela- 1;; v e of I'eflectorit is f 4 also essential" to'have't li ht stantlally at or in front of the' cent r' f th g ass bulb inclosfl lg smuch [as some.

source ositioned at'this' poixit. And, no

1' t upward' glare results owing to the efi'ect *0 one side. Icontemplate, forexample, a ply "ing my, invention to search-lights emp oyed- .to illuminatebuilding's and like-i I f a, reflector-adapted to freflect in;.and below- I ,a horizontal direction,.'-a "concentrated-beam] n of; light sharply defined onits upper side,

@5115? sp aced-with relation-t horizontal plane through the focus of the reflector and'gt 4 .verticabdimensiontand;positioned with rela- .tion "to the focus. of the'reflector so as tore; j. fle'ct inand below.- a horizontal direction sub tively. obliquely s a horizontalfplane assfiaj "upwardly, where light may beprojected substantiallyhori zontall withoutproducingupward glare.

4. Light" projection apparatus comprising 7 a reflector having substantially .acontour formed'by the revolution of a conic section, a light source positioned with relation to theing through-the light source,'and means adjacent said horizontal plane for preventing substantially all rays of light radiating either parallel with or relatively 'acutelyto lane from" being reflected by a concentrated beam pf said horizontal focus of the'reflector so as to reflect in and below a horizontal direction substantially all rays of light radiatin from the source other than those raysi'ra iating approximately horizontally, and means adjacent a ltGI'l-g zonta'l plane r .passingthrough the light.

source for preventing'substantially all rays radiating approximatleliyj horizontally from being reflectedupwa ly,' whereby a concentrated beam of h light may be; projected substantially horizontally 'withoutfl reflecting e substantially any light upwardly; 1' '1': 7

7 5." Light projection apparatus comprising ajreflector 9 having substantially, a contour. formed the'revolution of a conic. section and arranged to reflect a concentrated beam of light in andbelow ahorizontal direction, a 1i ht source positioned with relationjto the ocusof the reflector so as to reflect sub-. I,

i stantially no-light upwardly except in-the zontally without. reflecting substantially any light upwardly.-

6. Light pro ectioii ap'paratuseeoriiprisin Y a light source having an apprecia dimension, a reflector having a portion above through, the light source, one p'ortionof the le verticafi and 'a portion below -ahorizontal 'plane reflectorlbeing shaped and positioned with centrated beam horizontally, and the other 5o portion being shaped and positioned with' relation to the light source to project alconrelation to the light. source to roject a divergentbeamdownwardl'y, an I means adjacent saidhorizontal plane for" freventin'g [frombeing reflected upwardly su stantial lyf I approximately"horizbn f tally om theslig t source wherebyfa beani of light mayibe projected toTdistant, iie'ar' and intermediate r withoutproducingupward'glare. '60- all ra sgf radiatin 7 Light: projection apparatus comprising tioned below the light source in such manner;

4 ly, a reflector having substantia ly a contour formed by the revolution of a beam of light may y "10; Light projection apparatus comprisi'ch has substantially afcontcun formed ",by the a 1fevo1ution of one or more conic sections, and light; source positioned with-lielatiom to 1 the :focus or focigof the -eflectoriso that substantiallyall raysiofg light"striking'thesaid portion of theieflector aregrefle'ctediin and. ions of ai' roadway z; v j 1 having-portionsradially' displaced from the j if.

a light source, a paraboloidal reflector pos1- conic section positioned above the light sourcei'n such manner'as to project adivergent beam of light downwardly, the light source being displacedrearwar'dl and vertically with relation to the focusfo theparaboloidal reflector, and 'means adjacent" a for, reventing -from d war ly substantially all rays radiating proximately horizontally from the vertically ,horizontal plane throu h the. li ht source: I

ing re ected up;

displaced portions of the light" source,

whereby a beam of light may be projected I, 1 to'distant, near and-intermediate portions of .v V a roadwaywithout producing upward glare.

8. Light projectiona paratus comprising I sqii rcq. a parabo oidal reflector positioned Lat zontal plane through'the light source so as horizontally 'Qil j ct a concentrated be 3 of light "av-"considerable distance along a ,roadway, a""*concavereflector positioned at least in part on the other side of said. plane so 'as jdownw'ar dly' to project a divergent of light to near and intermediate'por .tions of thelroadway, the light source bein [positioned at the focus of the paraboloida reflector but ,havin "portions axiallyTand j vertically displace with relation to the focus, and means adj acenta horizontal plane a through the lightisource operative only upon light radiating approximately horizontally -.=from.the source for-preventing'such light E-from beingreflectedupwardly. i j

9.: Light pro ection fappa'ratus'v'comprising a reflector having a substantially paraboloidal portion, an

to the-said para loidalportiomthe curvature of the reflector being modified adjacent a horizontal plane through the; light source east inpar't'on one sideof ahori- 1-,

y a *light source positioned' with relationlto the focus of 'therefiector so astoreflect in and below a horizontal direc-. Jtion substantiall 1 all rays of=lightincident reflected upwardlyB-w ereby a concentrated,

horizontal y ing a reflector the major portion of w elow .a horizontal direction, the light source faxis-ofothe ieflector," and the reflecto'r'having,adjacent a;hoi'izontalj plane through therojected substantially without reflecting substantially any light. upwardly. i a

lightJsou-rce, a portion f modified in such displaced portions of the light source ap- .manne'r-thatrlight'fradiatingtrom the. said lsojj i reflector and positioned with relation to the horizontally without reflecting substantially any light upwardly.

11. Light projection apparatus comprising a reflector adapted to reflect, in and below a horizontal direction, a concentrated beam of light, a light source having a portion vertically displaced with relation to a horizontal plane through the focus of the focus so that substantially no lightis reflected upwardly, and a transparent container for the light source, the light source being positioned at or in front of the center of the container to prevent light being reflected from the interior surface thereof. to the reflector in such manner as to be reflected upwardly.

12. Li ht projection apparatus comprising a re ector adapted to reflect in and below a horizontal direction, a concentrated beam of light sharply defined on its upper. side, a light source having a portion ,vertically displaced with relation to a horizontal plane through the focus positioned with relation to the focus so that. substantially no light is reflected upwardly, and a transparent front cover for the reflector shaped and stantially any lig t being reflected therefrom to the reflector in such manner as to be projected upwardly.

13. Light projection apparatus comprising a light source, and a reflecting surface positioned substantially wholly below a horizontal plane passing through its focus, the reflecting surface being shaped and positioned to project a concentrated beam of light horizontall the light source being positioned imme iately behind the focus and immediately above the axis so that substantially no light is projected upwardly. r

1 L Light projection apparatus comprising a light source, and a reflecting surface of a horizontal plane passing through its focus and adapted to project a concentrated beam of light horizontally, the light source being ,placed in juxtaposition to the focus of the reflecting surface but'lying substam of the focus substantially tially entirely on one side along the axis and lying wholly above said plane so that 'substantially no light is projected-upwardly.

15. Light projection apparatus comprising a light source, and a reflector shaped and positioned to project a concentrated beam of light horizontally, the light source being positioned, with res ect to the focus of the reflector, rearward y and upwardly and in such manner that the concentrated beam of light is sharply defined on its upper side.

whereby a concentrated I fleeting surface beam of light shar of the reflector and be adequately illuminated.

ositioned to prevent subside,

substantially wholly on one side- 16. Light projection apparatus compriss ing a reflector, and a light source having portions radially displaced from the axis of the reflector, the reflector being so shaped and the-light source being so positioned with respect to the focus or oci of the reflector as to prevent light radiating from the source being reflected upwardly due either to the transverse or to the longitudinal curvature of the reflector and as to project in and below a horizontal direction a concentrated beam of light sharply defined on its upperside.

I 17. Light projection apparatus comprise ing a light source, a. reflector having a reabove and a reflecting surface below a'horizontal plane throughthe light source and arranged to project lightfrom both surfaces, the light source having a substantial dimension along the axis of the reflector, and the reflector being constructed and positioned with relation to the light source horizontally to reflect a concentrated ly defined on its upper side and 'downwar ly to reflect a divergent beam of light, whereby distant, near and intermediate portions of the 18.'Light projection apparatus comprising a reflector adapted to reflect, in and below a horizontal direction, a concentrated beam of light sharply defined on its upper and alight source having aportion vertically displaced with relation to a horizontal plane through the focus of the reflector and positioned with relation to the focus so that substantially -no light is rethe reflector having a sur face of substantial extent both above and below said horizontal plane for projecting said beam of light. a 19. Projection apparatus comprising a reflector and a light source, the reflector being so constructed and the light source being so positioned with respect to the focus or (portions of the source from being reflecte upwardly roadway may light due to the'transverse curvature of the re-- 20. Light projection apparatus compris-j ing means for projecting in and below. a

horizontal direction, a concentrated beam of light sharply defined on its up er side, said means including a reflector an a light source -so positioned with res ect to the focus or-foci of the reflector t at substantially no light is projected upwardly, and a transparent front cover for the reflector arranged to prevent substantially any light from being reflected therefrom to the reflector in such manner as tobe projected upwardly.

21. Light projection apparatus comprising means for projecting, in and below a horizontal direction, a concentrated beam of light sharply defined on its upper side, said means including a reflector and a light source so positioned with respect to the focus or foci of the reflector that substantially no light is projected upwardly, and a transparent container for the light source, the container being so shaped and positioned with respectto the source that substantially no light is reflected from the interior surface of the container to the reflector in such manner as to be projected above the sharply defined upper side of said concentrated beam of light.

22. Light projection apparatus for projecting, in and below a horizontal direction, a concentrated beam of light, comprising a reflector, a lightsource so positioned with respect to the focus or foci of the reflectorthat substantially no light radiating relalff tively obliquely to a horizontal plane'g,,;

through the light source is projected upwardly, means adjacent said horizontal plane for preventing from being reflected upwardly substantially all rays of light radiating either parallel with or relatively acutely to said horizontal plane, and a transparent container for the light source so a shaped and positioned with respect to the V w a source that substantially no light is reflected from the interior surface thereof to the reflector in such manner as to be projected upwardly.

e 23. Light projection apparatus for projecting a concentrated beam of light sub-- stantially horizontally comprising, a -sub stantially hemi-paraboloidal reflector positioned below a; horizontal planecontaining its axis, a lightsource ositioned rearwardly of the focus of the re ector in such manner that light is projected to distant, near and intermediate portions of a roadway without producing upward glare, and a transparent container for the light source positioned with respect to the light source in such manner that substantially no light is reflected from the interior of the container to the reflector in such manner as to be projected upwardly.

24. Light projection apparatus comprising a light source, a reflector having a portion above and a portion below a horizontal plane through the light source, one portion of the reflector being shaped and positioned with relation to the light source v to-project a concentrated beam of light horizontally, and the other portion being shaped and positioned with relation to the light source to project a divergent beam downwardly,

the reflector being so shaped and the light source being so positioned von one side of a transverse. plane through the focus of the reflector as to project aconcentrated beam of light along and below a horizontal plane .through said focus without producing upward glare, and a transparent container for the light source, the container being so shaped and the light source being so positioned within the container as to prevent the light reflected from the inner surface of the container from being reflected to the reflector in such manner as to cross said horizontal plane on the side of said trans-verse plane opposite to the light source.

26. Light projection apparatus comprising a concave reflector and a light source, the reflector being so shaped and the light source being so positioned on one side-of a transverse plane through the focus of the reflector as horizontally to project a concentrated beam of light without producing upward glare, and a transparent container for the light source, the container being so shaped and the light source being" so positioned within the container as to prevent the light reflected from the surface of the container from focusing at a region other than on the same side of said plane as the light source and farther from the focus than the light source.

27. Light projection apparatus compris ing a substantially llGIIll-PfiI'EbOlOlditl reflecting surface positioned below a horizontal plane containing its axis, a light source so positioned behind a transverse plane through the focus of the reflecting surface as horizontally to project a concentrated beam of light without producing upward glare, and a transparent container for the light source, the container being so shaped the light source, the. container being so shaped and positioned with respect to the light source and the reflector being so arranged With vrespect to the container that substantially no light is reflected from the surface of the container to the reflector so as to be projected upwardly.

29. Light projection apparatus comprising a concave reflecting surface disposed at least in part on one side of a, horizontal plane containing its axis, a light source disposed on one side of a transverse plane through the focus of the reflecting surface, and a transparent container for the light source. the container being so shaped and positioned that substantially no light is reflected from its surface so as tocross said horizontal plane on the side of said transverse plane opposite to the light source.

Signed by me at Boston, Massachusetts, I

Images