US1399749A - Headlight-lens - Google Patents

Description

o; E. COMMUN.

' HEADLIGHI LENS. APPLICATIUN FILED NAYS, 1919.

2 Shams-mm? a.

LEQQNQ,

' 0. 1L comm. HEALIGHT LENS.

APPLICATION' FILED MAY 5, |919.

Pam-m m13? wm.,-

Z SHEETS-SHEE1 2.

ZW @am tnwliiefemi :met ll, limit tene-ii eezteee.

.To all fwfmm it' may 'eo/,teem

lle it itiiowti that ii June 2li? Lltlift Theptitieipai object of tl'ie invention eubetzmtiftlly to elimiiiete the tip-weed gime from headlights; emi lit the seme time to impt'ove the distribution ont the liefiit throughout tl'ie dieteilt miti eezii'ei' portions :intl the side er' sides et the toeciwey, espeoioiiy tot mitoiiioliiie nee. llinotliiei oo jeet ie to' oliviete the ggleife which is peculiar to llehepefl ilzimente oi' iileioent iii, lllehopeti eectioiie, wlieti mieli iilemel ple/eeft in various positions iii headlights. l. fm'tiiei' object to eliminate the giet-e which i'eeulte from tile ere oiliiieiiiy given to tlie marginali petitions ot lieediiglit teile@ tere `when formed by the usuel methode.

il li ot the upward glare eomei.: fiom theceiitiel te (lieolosefi in my eit'oieeztiii eppiieetioii ll iwi/e discovered, the following eoiieeiiii'iglg liemiiiglit glei-e. 'llfiieii tile usuel termo oit' lamp tiumente ere employed iii the ordine y commerciali headlight "which is appro' tneteiy but not accurately potentieloioliil5 moet region ot the yiefleetoi. For exemple, with n, ltelieped tileinentl disposed enlistinitiallyin tlie vei'ticel Utiel plane oi? the i'etleetoi, eymiiietrioeliy to the :wie o'l the reiieetoe7 the glare spot, that ie the :ateo oi'.l the retient/oi ifi-om which moet ot tloe tipe. y inolinesfl rays are ie'lecteclj is eoiitiiietl to tlie iwtizil. region ot the teeetoi. With the tiioiiieut shifted about its exis into the horizontal :wird plaine, the gloire comes principally 'from tvv-o glare spots lo'ozttediii the vertical centi-el iegion of the ieleetoi? one eloove zmii the other below the exitti region ot the i'etleotor.

its Ytuitller dieclo'sed 'in my aforesaid appli eettion'tlie glatte item el! over tlie lieocilight may lie eliminated. tot e fletiiiite position oi the iight source lay meen@ et hoiitolitel piietxls, final; eitlitloiiel prot le.l ogeiliel' glatte limit loe oiitziiiietl by eeveil, l the elite i vettieel iilie wl/mieli tette iigglit item the tete spot-e' out olf tlio l' `oleieiei toitli by Hating' outwardly netti' fi/glatte produ-sing wititll l, i pio tetten ogemet gioie is that it petmitit e, oeiftmii movement of tlie iight eoiijcee .m oil :imaetioiis from the posesitioii in, i tlie horizontal, eloiie' etaitI tie et to protect :item gioie, time tl'ie lieeeeeity el? r v 'j iemfotely positioning tile oolfixvete 'for ineeeui'eejy' in the positioife ing oli the flight eoiii'ee it etioifle e much greater? ioiig range illumination.-

li have also discovered from eei'eii'fiii eiteiiiisetiojo @if at greet man?! iieziclligglit Yefleo tore that they (iepei't from. e perfect pome the tim wel that the eil'eetoi thist oiitweiii ii 3 is to cause glareprincipally :it the top ot' *,iie :eetli'aotoi"w in oiilei' to eliminate the gime inflileli stiisee from this souioe, l. piopo'e to provide the headlight lens meer ite upper erige Witli e horizontal prism of high ie'metive power tine bending downwardly the i'eys which are ietieotefl from the upper edpfeeif-tiie reflector.

it is witten' desirable to extend'tlle letelol yot the beam in oidel'4 tlmt the sides of the tomi muy be properiy illuminated, olii'eotly in advance oi the headlight. Ars Ver tieatl retreating* prisme 'will not give a, wide letemi dietrllmtion oi the light rays, ll thereioi'e pi'opoee to employ internal reflecting primes tot this purpose. v

My invention is particularly exemplified inthe accompanying drawings iii-Whichlfigme l e schematic clewingof e ver tieei Section through a. reflector having an outwifm'd tiere et its edge9 showing the ieeetioii of the Ii'ppei glare center;

Fig. is a, sehr-emotie tient View of the Hector oit F Si, sloot/ing tiieapproximete shape eetl Neotion et the upper glare spot; "igt 32u; ,eooemotie drawing of at vertieiti longitudinal section o'l' tlie eefieotoil5 showing' tlie contee et sie-veeel my@ when the light eem-ee ie moi/eti teem/emily litem the tocas;

fitto." "liliue wliiie present itiventioii I i. ie

Fig. 4t is a front vienr of one embodiment of my invention;

Eig. 5 is a section on line of lig. 6 is a section on line (iL-45 of c.

i, 'i is a front View of a. lens Sho-wing one arrangement ot horizontal prisms;

Fign is, a front View of lens showing e.' modified arrangement o horizontai prisms;

Fig. 9 4shows cylindrical iens :s ifihich may he used as vertical ions ribs to distribute light iateraliy;

Fig. wie a modified arrangement of ey..- lindrical lens ribs; v

Fig. ll is a section of an internal refiero ing prism which may he used as a vertical iene rib;

Fig. l2 's a front View of an embodiment of my invertion in which vertical internal reiecting preme and reflecting prisms are alternated; I Fig. 13 is a section on line .i3-1S ot' Fi". l2;

Fig. 14 is a. front view of a preferred enihodiinent of my invention. in. which the rertieal ribs are iiexedg' Fig. l5 is a section on line -15 T hg. 1.4i;

Fig'. 16 1s a section on iine .i6-w16 of Fig-r, n14;

Fig. 17 is a detail oi one oi the ribs shown n Fig. 14:;

Fig, 18 is a section on line 18ml?) oli' Fig. 19 1s section on line lmlf? of Big. 17;

Fig. 20 is a section on line 20-26 oi' Fig. 17; and

lig 2l is a section on line 21,-91 of hree factors must be considered in the Correction of headlightsto eliminate Iglare or the upward tendency of some of the light rays. These 'factors are the shape of the light source, its position with respect to thc focus, and the inaccuracy of the refieotor.

The light source which is niost commonly need in l'ieadlights is the Manila (l niiniature, iainp having a spiral filament which is lient into a V-shape. ln y'nact-ice, the plane oiE the i! may he either horizontal or vertical, or may tal l any angular position between 'the horizontal or vertical, the position dcpending;n upon the position of the lamp hulh in itzf'soclcet ln order however to correct the lieain for glarey regardlese` oi' the angular position ol the V it is necessary to design the lens upon the assumption that thc light source is a cone of iight generated hy rotating tho tilanient aliout its hiscctor.

ln Fig'. l .l have diagrainnatieallv Shown a moss-section through a reflector l; oithe ordinari' paraholoidal tvpc havin.;r an out'A ward flare at the rixn hclwccn the pointsI and il, This outward flare dcparthI from the ffii@ true paraholoidal surface which would follow the dotted lines fl. Thisoutward find is a very common inaccuracy in the design of reiectors ordinarily found on the market. A lens 5 having:r horizontal rcfracting prisms G and vertical prisms 7, is Secured irrthe refieetor in. any suitable manner, the horizontal prisms` having decreasing refracting power from the center of the lens niwardly and downwardly. The prieni 8 at the extreme upper edge of the reflector, however, is provided with high ref'actiug power to correct for the outward flare of the relector. The source of light is represented at l., in full lines, as a conical figure, and is located at its proper position with 4its axis coincident with. the axis of the reflector and its base at the focus F. The source, l is also repre-sented hy dotted lines displaced hachwardly along; the axis of the reflector. 7With the light source positioned as shown in full line, the rays from the. rear portion of the lightsource l, and incident to the reflector at point 9 on the reflector, are lient downwziardiy and emerge troni the lens at l() produel 2g no upward filare. A ray` from the apex oi the source, also incident at il, einer en from the lens at ll in a downwardly direction. Rays from the rear aud apex of the source, which are incident on the tiaginig portion oi reflector R at lL-. are lient downr' diy by the upper horizontal prism S and emerge at lf3, i4 respectively, Thus with the source, l properly positioned.l all rays incident to the refiector are lient downwardiy and ,glare is elin'iinated.

When, however, the light source is iinprog/)early positioned hack of the focus l". as shown in dotted lines, rays from the source incident yto the reflector at points 9 and-l2 einer-ge as indicated at 15, lo. 17 and 18. and are. all directed ulnvardly. Thus it is clear that all rays in the upper half of the refiector l( will he displaced upwardly when the light Source is moved llackward from the focus. This upward displacement, l have tound, in greatest at the point S) whose distance ahove the axisl ofA the reflector i ,QI/7, tunes tno focal length of the reflector.

in order to understand thc full significance of this fact.y suppoac the vertical prisms T otI thc leus 5 are olnitted and one is lool iu} r into the headlight jfrom a considerable di tance ahead with his" c ve at point ll, as shown in Fig.' Ih then with the light source properl \y positioned in the reflector lL rays incident to the reflector ll at points Sl. 'l2 are directed h v the horizontal prisms hclow 'the levei ol the eye aS indicativi liy full lines lil, Zfl. lf' now the light source is pushed hackwardly. the ray incident at thc point El is; not retracted suflicieutljv to llc directed helow the level of the c ve. hul' reaches the eye at li as Shown by the dotted line 2l, and

:tieneL v thin-i the eye loi'iltinlem einen; rey fil eeen;

iti

e. `fil-,dere epot et @n the other bend the rey ineident et iii, elt'hough upwardly chrected", posses below the level ot the eye et lill, ond the'eye therefore doen not receive nny light trom l2, end therefore the glare spotdoen not ontendv trein point 9 to the point i2. liteeord ingly the @loro :eren 4doen not cover the ein Vtire upper. holt oit the reflector but in et linew ited extent. lior e denite position ot the 'light eonree this @loro rtree will beve the Agenerei position sind shone shown by the ehiided etree t3 oil Fig. SE. lit the light-source in moved envoy from the toons the ere-e. 255i beeonies larger endif moved neiirer the eroe ndbeeoines erneller.

By eoverirrt,v thin errenty with' vertieel re fronting or.reflectingl elemente designed to il to nl love the hL to tiene throngro. the .lorie-r belt ot the iene Without ,leterei ditlneion. The

light linee in ti indicate the path etlight reysy through the vertical ribs oir the lone.

.its e concrete exemple oit one torno. which the iene oit i nitty tor e. speciiied Sharpe end ponrtion ot the light Source, the horizontal primis may hovethe ongles o'lf elope given in degrees in the following trible, the prisme being teilten in. order downvverdly lond lrorn lett 'to right: l0; t5. 6.5, 4.5;

5, t, t; eee, r te, en. me', me', i, i255 didnse the light lnterelly to the eide@ oit the rond, the glere thus caused by the improper position ot the light source iney be reduced end een be entirely eliminated :trein the eenn trel portion ot tbe been; 'tor e Substantial displacement of the light source. lin Fige.

' et, 5 end t5, il ilove shown one embodiment Aot my invention tor time loterelly diilneing the light. The iene Q3 is provided with horizontel prienis 2t eind 25 which beve tiet euri'incee' end preterebly decrease in refractive newer trono the center' oi the lens both np- Werdly ond downwardly, end loterzilly on either eide'ot the center. The number ot horizontal prisms 25 on the lower holt of the lens 2B lio/ve been inereesed relatively to the number ot prisms 24 on 'the upper helft ot' the lens in order to rive a more emot eorreetlon nlE the beam ot light incident troni the lower heilt oit the reflector9 end in con* sequence provide better long dietiince illumination, ineeinnch es the light from the lower heit of. the reflector is depended. nioon for long distance illnniineition.A lin linz. Il l here indicetedthe arrangement oi the horizontal `rierns; by dotted linee end in Fin; i' by tnll inns. llt is to be noted that the Lipper horizontzil prism i is of relatively high. retrete tivepowe'r tor the purpoee oit Correcting,f :tor the ontwerd tiere of the retlectol es han been hereinbeiore pointed ont.` The upper portion of the'leneis; also provided with verti'cil cylindrical ribs 2G of the special type disclosed in Fili. l0. .fte the gloire tir-st no peers in the upper veltieel central region oi the reflector, the refractive power ot' these ribs is therefore .greatest et the center and deeleesen lenterellyA outwardly toward the edges ot' the lens es cleanly shown iby the sectionel view, liig. (L '.l'hese ribs nre looated on the foce ot' the lens opposite the horizon tel prisms end extend only slightly below the horizontal center line ol' the lens. f lhev could ot course extend over the entire 'lnooioi" the lens. but ne the prineipel ,glei-o snot is lower part ol the rellootor is need lor innig i, eve; zii, e; ne. ee, et; ei,

ln iig. 3 .l here disclosed en elternotlve arrangement ot horizontel Vnrieins 27, in which the prisent ore ell et .enbetentielly the seine Width, the number on the lower portion of the lens being siibntentielly the seme es the number on the upper portion oi. the lens. llt ie obi/ione that this eiiingeinent oi' liorinontel prisms; een be need with any oi the einbodiznente et vert-lool prisms herein disclosed.

.For e s'iiecied shrine and position ot the light source the horizontal prisme may lieve the angles et slope given in' degrees in the following table, the priori e being teken in order downwardly end from lett to right: 6.5; in. et', it; i. i, 5;. it, e5. 4.5; een, i; j

llt ie well lrnovvn tliet eylindricel lenses provide one oil beet meent for dietribintA mg light leterelly es they (lilloise it smoothly. end Without e'. e. Without elternote darli .and iight arene. lin Fig. 9 il lieve di closed tivo sncli eylindrieel telnr-eey or ribs 28 which mightbe employed vertical ribs to cover the opper portion oil e. heedlight lens. Such leneee however when ol' short radius. ae would be neeeezeery over the @ein ter ot' the flore spot., would require e, considerable'thicknessof gloss in order that the headlight lens might not be week et the junction oif 'the cylindrical ribe. To overcome this diltienlty the lensee may be divided un into parte es indice-ted et o, E), o, d', e, if, g., il... if.) ond y" and reerrenged as shown in Fig". il). The arrangement ot hlg. l0 has the edditionnl iidventnge .in that the reiys which lieve the greeteet tendency to glare receive the greatest deflections. in both Fins. Si and 10 the rays ot light have been indicated by light lines, incidentie the flat fece ot the lense-.s end deflected by the cylindrical tenes. i brackets :ire those luivinlggF the greatest tend". eney to glare. ldihiie l lieve illustrated con?` Vvor lenses. lt wish it to be eleeriy under n ot :in inter comprising' 'two et en ecute lili iet

The rays inclosed byf( lil@ angle. Light .rays 54, 55 and 56 are shown reflected by the internal surface of the member and emergent at 5T, 58 and 59 respectively. it is evident from a study of Fig. 11 that if the entire glare area of a headlight lens were covered with members similar to 32 that the light rays which would have a tendency to produce glare would be erred embodiments of my widely diffused and the width of the beam extended to nearly 18H0. Such construction would not however be practical because the grooves between adjacent elements 32 would be relatively deep and would collect dirt very easily. l therefore propose to employ such internal reflecting members 32 in combination with cylindrical lens ribs such as disclosed in Fig. 1f). This embodiment is illustrated in Figs. 12 and 1S, in which 23 is a headlight lens having cylindrical lens ribs 3() and 31 and internal reflecting meins bers 32 arranged in alternation with the ribs 31. it is understood that these vertical ribs may be used in combination with any of the sets of horizontal ribs herein illustrated. c

Figs. 14 to 21 inclusive illustrate the preinvention in which the lens 23 is provided with horizontal ribs $33 to 41 inclusive which are of the flexed type disclosed in my co-peiiding application above referred to. The remaining horizontal ribs are flat. as no particular advantage is gained in making them flexed. The top rib 8 is of high refractive power for the purpose of correcting for the inaccurate flare of the reflector as hereinbefore mentioned., rlhe edges 42 of the flexed ribs are convex at the center 425 and concave near the ends 43. yBy means of these flexed ribs it is p ossible to obtain better long range illumination andat the same time avoid glare. The vertical ribs 44 are also of the flexed type shown more in detail in Figs. 17 to 21 inclusive. These ribs 44 are so designed and placed on the lens that the refractive power decreases in all directions from a point substantially in front of the glarel center. lhus the greatest possible illumination along the axis of the beam is obtained consistent with adequately covering the upper glare area. ln case more lateral illumination is needed the refractive power of thevvertical ribs 44 may be varied upwardly and downwardly only, or laterally only. In the latter case the ribs would not be flexed, but of the form disclosed in Figs. 4, 5 and (3,' or the form shown in rigs. li, 12 and 13.

In Figs. 17 and 21 inclusive l have illustrated in greater detail a vertical rib 44 of the flexed type such as is employed in the embodiment illustrated in Figs. 14, 15 and 16. The center line of the rib is flexed as shown by the section view Fig. 1H. such flexed edge being made up oftwo straight lines 45 and 46 which join at a point 47 which is at the a proximate center of the longitudinal lengt i of the rib. The edges 48 of the rib are straight throughout their length as shown by the sectional Aview Fig. 19. l Thus the rib 44 has considerable depth. at its center line 20-20 as shown in Fig. 20 and no depth at its ends as shown in Fig. 21, Thus, referring to Figs. 1.8 and 2() a ray 4S) incident to the rib above its vertical center is deflected downwardly and a ray such as 5f) incident to the rib below its center is deflected upwardly, but both of these rays would be deflected laterally :is at 5l, in Fig. 2f). A ray incident to the rib near its edges 48 would be very slightly deflected either upwardly or downwardly as is illustrated at 52 in Figs. 19 and 21. For similar reasons a ray incident to the rib near its ends would be only slightly deflected laterally. intermediate Sections of these ribs will deflect light rays by varying amounts, so that each rib distributes light continuously and.,without striae,

Vertical ribs of this character have three distinct advantages: ln the first place they cover the upper glare spot in the most ellicient manner; secondly, they distribute the light laterally without strizr. and thirdly` they meet the surface of the lens at their ends so that there are no rough places or creases to collect dirt.

rlhe terms horizontal, vertical, etc, are not necessarily to he construed in their narrow and exact sense but are preferably to be construed to include directions and positions which are approximately horizontal, vertical, etc.

I claim:

1. ln a headlight havin, a reflector substantially paraboloidal ut inaccurately shaped at its edge, the combination of the reflector, and a lens having horizontally disposed pi'isinatic. ribs on one face thereof, the refractive power of which decrease from the center of' said lens outwardly, the rib at thc top edge ofsaid lens of higher refractive power than the other ribsA ranged to correct for the inaccurate shape of the edge of said reflector.

2. ln a headlight having a reflector substantially paraboloidal but inaccurately shaped at its odge. the combination of the reflector,` and a lens having flatefaced horizontal prisinatic ribs on one face thereof. the refractive power of which decrease from the center of said lens outwardly in all directions. the rib at the top cdge of' said lens of higher refractive power than the other ribs arranged to correct for the inaccurate shape'ol' the edge of said reflector.

3. In a headlight havingr a reflector substantially paraboloidal but iiniccuiatclv shaped at its edge. the combination of' the reflector, and a lens having horizontally Lemme mi disposed prismstic ribs on one face thereof? #the refractive power ci. successive ribs decreasing from the center et said lens 0ut- Warclly, the number of said. ribs disposed be low the horizontal center line of the lens` being gres/ter their the number disposed aber@ such center line, certain et seid ribs comprising e, plurality et laterally disposed. sections having ditierent refractive pcwers tile refractive power ci? each rib being greatest it the vertical center iine of strict lens Junclfthe uppermost rib having high refractive power arranged, te correct 'tor the inaccurate shwe of the edge of the re- Hector.

4.-. .t headlight lens having horizontally disptised prismutic ribs on cire fece thereof,

vertically isp/Used ribs having cylindrical surfaces covering; at portion. oi? the other face of Said lfm-s and-Vecuy dSPOSecl interiwil 2e reflectie@r `:memliners arranged in alternation with certain of seid vertical ribs.

5 t headlight lens having vertically dispcsedribs having cylindrical surfaces covering a. portieri cf ont farce of said lens, and, 35

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