US821310A - Compound reflector for artificial lights. - Google Patents

Description

PATENTED MAY 22, 906. 0. A. MYGATT.

COMPOUND REFLECTOR FOR ARTIFICIAL LIGHTS APPEIOATIOH FILED JULY 13, 1905.

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ffietented meg Application fileii July 13. 1906; 591ml llo. 2622,5653

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therein to the eccornpenymg diner This mren n l: es to shades one re The ob ect of the invention is to so soon bins with a. reflector or slrsdeseliector com posed of prisrnetic glass an auxiliary or coop"- erstmg T cover therefor as to increese the el oiency of such reflector. The invention may shade and reflector with electric incandescent lamps enri other light sources; and it consists, essentially, of s combination of dilier ent refiectingeurfsces and produces results unattainable by any other means W'l thin my knowledge. y

it is a well-known fact that reflectors mode of transparent glass havingthe outer sure feces formed in prismatic rib wings of suhstsn tislly ninety-dc ree angles are highly efficient as reflectors en not subject to deterioration, as is themes with reflectors hsving polishe metallic surfaces. As prisms of ninety degrees receive the incident rays at angles of substantially forty-five degrees, "which single is less than. the angle at which total rcfiection takes piece, it follows that e portion of the light is transmitter]. hy such reflectors. in some cases this is sdvsntsgeous, as it furnishes illumination in the regions shove the level of the reflector; but in other osses it is decidedly ohjectioncble es, for exemple, when a. reflector is in such. position that the transmitted liht would shine directly into the eyes. In. such ceses it is desirable that c. shadethst is, an opaque suhstenceshould be used to intercept the upward reys oi light Such shades are commonly constructed of some opaque substance having is white inner surface, which sets as a. diffusereflector. Such diffuse-reflectors, however, are less eliicient then prismatic gless, end esecislly ere incapable of concentrating the light in any particular direction. My ire roved rcilcctonshsrie secures the eclventeges 0% both the prism-gloss reflector sncl the opaque shsrle with white refiectingsur'feces. In practice I prefer to use e prism-reflector of conical shape, since this is the shape to which low he used es s, combines the prism-glass reflector,

the soperir posed sheds or covering most reerliig' sttscherl; but I do not re sell? to soy particular form or CQXTtQU." reflector.

Figure l s s is risnietic-gloss reflector.

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e of pestehoeri-eri hotly oi the re'tlec Xx an enlarged cross-seci e tor coves-so, shoutl 4 1s 9. diagram. showing lines 1 r light-ref by the prions; oi? the 5 anti 6 are iiiegrsins showing hot t ego reflection o the reflectors singly and cons bins-d. X

The cover 2 18 preferably applied ireof the iectcr 1,20 as to rest only on the spel -ice prisms. As Will be seen, the cover s tiellyicoiresponris in its truste -conic V with the cooly 1 of the reflector. some general foot is true of" other terms. 1

Fig; 4 shows the line of reflection of e Halli)"- rey, a b c d, by one of the prisms of reflector 1 as Well understood in, this art.

Fig. 3 shows a. horizontal section of my combine-ti shmie snrl reflector, in which 1. is and 2 the slieqlc or cover. This shade or cover rosy be made or lain White oeper or cardboard, or the eerd card may e White insi le enri of any desired color outsicle. Opel gloss, white sheetcelluloid, sheet-elu'miniurn, or any ther sci? ehle material may he useol. The terie, chosen is formed into e one is mo shape of the prise gloss i d. shade thus formed is i leceo so to or and be supported 1. he 1' iiector i 1 light transmitted by the prr 1 tells upon thewhite or age :oic surface of the cover 2 soil is reflecto weirdly through the trees-times."

reflector, The increese in refiecten thus pro .oeri is clearly shown in t i 5, the curve snowi en' B the com .I 'oof the eomhinetion, per :iesirerl to reflect es imich es directly below the e fiector, is shown in the Fig. which A shows the distrilr tion ohtsinee. the trensosrent-glsss re.

e 1 the ellstrihutlon ester. by the r ft or intensity, Fig. from reflector l "he. erlvsntsge lorly where it is possible the White inner surface i no White inner in ominection" shsrle also improves the resulting illumnm r ya ' evenly-illuminated surfaces. I

tio n by preventing streaks, spots, or unam aware that an attempt to accomplish this purpose has been made by painting or enameling the outer surface of the prisms of a prismatic re- .fiector; but I have found it impossible to secure in this manner resultshaving any advantages whatever over the white surface or diffusing-reflector alone. That this must be the case will appear when it is considered that the reflecting power of prisms is destroyed as such when their surfaces are brought into optical or molecular contact with other substances. The result is that a prism-glass reflector with the prisms painted or enameled with a white substance is less efficient than a similar-shape white, opaque, or cardboard reflector. My cover 2 does not touch the plane or reflecting faces of the refleeting-prisms.

Q What I claim is- 1. The combination with a glass reflector having risms on its outer surface, of a separate lig t-reflecting body, with whitish interior surface said inner surface being smooth and lying in a curve close to the apexes of the prisms and above the depressions between the prisms.

2. The combination with a frustum-shaped glass reflector having reflecting-prisms on its outer surface, of a similarshaped opaque refiector of uniform thickness lying in a curve close to the apeXes of the prisms.

In testimony whereof I ailiX my signature in presence of two Witnesses.

OTIS A. MYGATT.

Witnesses:

H. E. NASON, ROBERT KELLY, Jr.

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