US1824894A - Color screen for reflectors - Google Patents

Description

INVENTORV 4 ATTORNEYS A. HOPKIN, JR

COLOR SCREEN FOR REFLECTORS BY diam Filed July 16, 1928 Sept. 29, 1931.

Patented Sept. 29, 1931 ALFRED norxrn, 1a.; or enrmnnnrnrh; rENNsYLvAnImAssIcNoR 'ro rn'rsnnnen REFLECTOR com any, ,on'rirrsiannen, rnNNsr vAmA, A CORPQRATION"QF "PENNSYLVANIA coL-oaf scnnnn ron R-EFLnc roRs Application fi led Jul s, 1928. Serial No.293, 1'15.

This invention relates to improvementsiin color screens for reflectors. I

' It is an l of:the'invention. to com pletely differentiate in color the bea1npro-1 jected from;a reflector and the direct or spilled lightfwhich:islunreflected.

Iv am aware of the fact that attempts have heretofore been made to control the'color of light rays in such a Way as to color difierently the rays .issuin'glat different anglesfi'om a single source. There are advantages, however, injso designing the color screening structure as to difierentiate more or less exactly between directand reflected light. These ad. vantages are particularly apparent when the screen is used in connection with asubstantially parabolic reflector such asiis used in doors as a spot-light forilluminating' a par-. ticular object or area in'a show-window and such as is used-out ofdoors for the .floodlighting of tall buildings; It is possible by means of this invention to illuminate the nearby lower portions of: a building with the spilled'or direct light'ofIoney-color and to,il'

. luminate the top of the building with a shaft or beam of light .of a different color, all from the same lamp source- It is also possible to produce in a show-windowa difiused direct light of one colorrand ;aTspot-Iorbeam of a difierent color, all from a single source. To

accomplish-these results simply and directly and with inexpensive but effective screens, is one of the purposes of this invention.

.Further objects of the invention contemplate the provisionof acolor-screen. device mounted upon the reflector itself rather than;

the lamp so: asto permitadjustmentof. the lamp for focusing without affecting the light-: tight relationof the screen to the reflector;

the provision oft-Ya two part color screen. so I designed and'mounted as-tofacilitate lamp replacement by an arrangementsuch thatthe outer portion of the screenis independently removable and gives adequate access to the lamp and finally the importan'tprovision of a color screen sodesignedas to permit of adeg I screenshown at 5 comprises a tube: of glass,

quate air circulation for cooling.

"Where lamp and reflector units are :em-

wardly, or at some intermediate angler Each light of the bank must be individually focused and directed. The heatrdeveloped by the bulbs'in a few minutes operationis such as to sarily pass between, the bulb and the color screen in so doing. The slight overlap of the convex portion ofthe screen beyond and in spaced relation to the margin of the'tubular portion thereof makes this circulation possible while preventing the escape of light.

The drawing shows in axial section arefiector; ;of approximately parabolic contour equipped w-ith'screens embodying this invention, a lamp comprising a sourceofilight being indicated in its properrelative position by means of broken lines.- v

- The reflector 1 maybe made-to receive any.

desired light 'sourcesuch as the lamp indi-: cated at 2. The drawing shows the lamp bulb so disposed within the; reflector that its filament indicated at 3 will be approximately at the focus ofthe reflector to the endthat the refiectedrays of lightfrom'the lamp may be substantially parallel. It is not.essential to this-invention that the reflector-be parabolic or that the rays issuing therefrom be parallel,.sinceit is frequently desirableto havethe rays converge or diverge to produce different effects." In referring herein to a beamof light, it is intended to specifymerely the reflected rays irrespective of whether they are parallel'ornot, unless otherwise specifiedg." Inaccordance with this invention two separate color screens are employed, either one of which may be omitted or else made of colorless transparent material whereit is desired that thecolor of the light emitted from the source at 3 I should ,be unchanged. That celluloid, mica, quartz or other material which is light transmitting in the sense that it is either transparent or translucent; As above indicated, the tubular screen 5 may be colored the reflector with which the screen is used. Itwill be noted that the screen 5 is of sucha length thatit intercepts substantially exact.- ly the light passing through source 3 to the reflector 1, and no other light. The particular reflector illustrated is a well known type made of glass of which the outer. surface is silvered to provide a mirror having a circular outer margin inon'e plane. When used with such a reflector, the tubular screen 5 will .be of such a length as toextend exactly to an imaginary cone described within the reflector from themargin 6 of the reflecting surface at the base of the cone to the filament 3 at its apex. This arrangement insures that screen 5 will act on all ofthe light to be reflected andupon none other. The screen 5 is seated in a shoulderin the'refle'ctor to insure against the escape of any .uncolored light.

. :Screen 10 is so designed as to transmit substantially all of the direct or spilled light issuing from the source at 3 withoutaffecting in anyamaterial degree any of the reflectedlight. To this end the dimensionsof-screen 10 are likewise such that irrespective of its position within-the reflector, it will overlap the margin of tubular screen 5 and terminate substantially' at theimaginary cone referred to above. .The particular form of screen 10 which is illustrated is preferred, all parts of such screen being substantially equidistant from the light source so that there-will be a' minimum of refraction of light passing through the screen.

It will be found possible to use avarietyof different means for flxingscreens iiand 1-0 in place-within reflector 1. The mounting device illustrated -comprises a hook 1 1 which engages over thereflector bead12. The hook isoffset at 13. and extends axially along the interior wall ofscreen 5' at 14 to :a further offset at 15. The two offset portions of the hook are apertured and.-a rod.16 is slidable through the aligned apertures under the compression of spring 17. a 1 The rod 16is-curved back upon itself at 18 for engagement with the outer peripheral margin of screen 5 and :is reversely curved at 19 to engage the peripheral margin of screen 10. The device is thus adapted to maintain the screens in their proper relative positions, not only with respect to each other,'but'also' with respect to the neck of reflector 1 toward which spring 17clamps screen 5. It will be obvious that other forms of screen mounting devices may be used. p

One of the important advantages'of the structure illustrated is the fact that the screen the fact that. during. theIChristmasfholiday season a green screen maybe used at' 10 and a red screen at 5 to produce from a single lamp source a green general illumination in a show-window and a red beam directed upon a particular object or set of objects within the window. By way of further example, it is pointed out that a single lamp sourcemay be used to illuminate the base of a building with direct light of one color, whilethe more distant summit may be illuminatel by a'beam of light of 'a' diflerent color. Of course, in any case one of the two colors may'beclear white light transmitted by an uncolored screen or trans mitt-ed through the space where such screen would be it it were used. Ordinarily it will be necessary to screen or otherwise reduce the intensity of'unco'lored-lightto avoid the possibility of subordinatingthe color." 7

' I desire to' make-it clear, moreover, thatin referring to the illumination of certain ob jects from asingle lamp source, I-do not mean to infer thatonly a single lamp and reflector maybe employed within the contemplation of this invention. '.-.On' the contrary, I refer merely to the production of two different types of colors of illumination segregated from each other ineachindividual unit-and thereby distinguished fromillumination which might be effectedby lighting one object er tirely from one source and another object or area entirely from a difi'erentsource.

-11 claim: '1

1. The-combination with a reflector, of a tubular screen and aconcave screen therein, 'togethed with a clamp provided with a hook for" engaging the reflector and reverselycurved portions for engaging said screens. 2. The combination with a reflector having a lamp receiving opening in its neck, of a color screen applied to said reflectoraboutthe neck thereof, and comprising :a lamp encircling annular portion and a closure portion, said color screenbeingformed to provide marginal opening between said portions, in communication through said first mentioned portion with said neck, whereby air is adapted to circulateabout a lamp within said reflector and color screen.

3. The combination with a reflector hav ing an apertured neck,- of an annular color screen element applied to the reflector about the neck, and asecond color screen element mounted in spaced relation to said first element, whereby to permit air circulation through said first element and said neck while intercepting substantially all useful light other than that intercepted by the first element.

4. In a device of the class described a light source, a reflector associated with said light source, a light transmitting means positioned to intercept substantially all light passing,

from said source to the reflector, a light trans mitting screen withln said reflector and v spaced from said light transmittting means,

said light transmitting means and transmitting screen being of different colors whereby to diflerentiate between the beam of light leaving the reflector and the light passing through the screen. 7

5. In a device of the class described a light source, a reflector associated with said light sou rce, a light transmittting means positioned to intercept substantially all light passing I from said source to the reflector, and a colored light transmitting screen within said reflector and spaced from said light transmitting means whereby to diflerentiate between the light leaving the reflector and the light passing through the screen. 7

6. In a device of the class described a light source, a reflector associated with said light source, a light transmitting means positioned I to intercept substantially all light passing

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