US1621360A - Incandescent lamp - Google Patents

Description

March 15 1927.

' 1,621,360 R. N. FALGE` I'NCANDESCENT LAMP Filed April 22, 1922 figa JNYEAZT :7H HUBERT AZ'. Ear, 5E',

ROBERT N. EALGE, E CLEVELAND, oHIo, AssIGNoR 1 prevent the f lthe filament. -.\\v

Patented M ar. 15, 19)27.

UNITED, STATES vPfr.rieur QFFICE.

To GENERAL ELECTRIC. CoM-v .PANY, .A CORPORATION 0F NEW YORK.

INGANDESCENT LAMP.

Applicatitm` filed April 2.2, 1922. Serial No. 556,080.

I My invention relates to electric incandescent lamps for projection purposes and more especially to such lamps for use in automobile or other vehicle headlamps, though my invention is of advantage in any rcase where, glare is objectionable. It has been the practice in most cases to use clear glass bulbs for suchilamps and, because such construction is desirable from. the standpoint of manufacture and on account of the p-ossession of desirable characteristics such as greater strength and freedom from strain, such bulbs have been made with vthe front portion thereof conforming substantially to the surface of a sphere. is accurately positioned in' the'center of'such sphere, no particular trouble arises. 'However, if the filament is not at the center, the

image of the filament is not reflected backv ,upon the filament from the front portion of the bulb but is reflected back to a position at' one side of the filament and this causes trouble. No-glare devlcesrwlnch are used,

for instance in automobile headlamps, ordiynarily require a definite position of the'light source and the creation of a secondary light sourcespaced fro'm the filament 1.cnds,'ob' viously, to cause such devices to fail ,in their function. The result is a glaring spot which appears on: the reflector. .A similargresult Y will `also'bev obtained where `the bulb departs slightly fromthe spherical contour although the filament may be accurately positioned. In both cases the trouble arises chiefly from the fact that amore or less definite image lof the filament is reflected ba'ck. l The object Vof my invention'7 is to correct this' trouble.

' According to my ferred form ay applied to bulbs of the usual shape, the bin is rippled so asto cause the `light rays which are. reflected back from the` substantially spherical front portion to follow multitudinous directions, or in other mords, to dis` erse or r1 ationof a definite image of In the drawing Figure 1 .is a partially vertical section showing a lamp embodying my invention, lsuitably mountedin a para- `When the filament 'rugation or rippling of the bulbV is invention',; in its prediffuse the same and" of the same; Fi 3 is a plan partially in section showing t e lamp and indicating Vthe directions taken by the reflected rays; Fig. 4 is a front elevation of the'same; Figs. 5

`and 6 arel similar views of a modification;

and Fig. 7 is a View showing diagrammati- `cally the reflection of light rays-1n a lamp as heretoforeconstructed.'v

Referring to the drawi g, 10 is the bulb of an electric incandescent lamp having tlie usual base 11, said lamp being mounted in ay bolic' reflector; Fig. 2 isa front elevation headlamp of which is shown the parabolic Y reflector 12. The filament of the lamp is shown at L13. The front portion of the said bulb, which is substantially a portion of a sphere, is covered with a series of corrugations or' ripples 14 which may be concentric as shown. In Fig. 3 the effect of vsuch core shown. 'lhat portion of the light rays Which-is relflected back from the front surface `of' the bulhis dispersed or diffused and this prevents the formation of a definite imageof the filament. In Figs: 5 and f5 is illustrated a modification in wluch the front of the bulb is fiattened, and it'is provided' with corrugations or rip les. In Fig. 7 is illustrated the undesirab e results obtained with the construction of bulb heretofore used. The filament 13 in this particular case happens to be offset from the center 15 of the spherical front portion ofthe bulb.` Y Thisresjults in the formation of a definite vimage 16 of t-he filament, which, as hereinbefore explained, tends to cause objectionable glare.

What I claim as new and desire to secure An electric incandescentlamp for ve- ,hicleheadlamps comprising a base, a concentrated filament. and. a clear lglass v bulb vbyjLetters Patint of the d/nited States, is v hicle head-lamps comprising a base, a conri ples so as to prevent the back reiection centrated filament and a. clear glass bulb o a definite image of the filament withoutv having its wall of substantially uniform a'ectingl appreoiably the light transmitted 10 A thickness throughout aiid having that portherethrough. 5 tion thereof opposite to the base of the lamp In Witness Whereof, I have hereunto set of 'Substantilly spherical contour Ibut havmy hand this 20 day ofvApril, 1922. ing thereon a, plurality of slight concentricY l ROBERT N. FALGE.

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