US1408875A - Beflectoe - Google Patents

Description

W. V. FOLEY.

REFLECTOR.

APPLICATION FILED MAR- 12. 1918.

Patented Mar. 7, 1922.

2 SHEETS-SHEET l- W. V. FOLEY.

REFLECTOR.

APPLICAT .12, I918- 1,40 8,875. Patented Mar. 7, 1922.

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H UNITED STATES WILLIAM VINCENT FOLEY, OF NEW BRUNSWICK, NEW JERSEY.

PATENT OFFICE.

REFLECTOR.

Specification of Letters Patent.

Patented Mar. '7, 1922.

;Application filed March 12, 1918. Serial No. 222,004.

To all whom it may concern: 7

Be it known that I, VVILLIAM VINCENT FOLEY, a citizen of the United States, residing at New Brunswick, in the county of Middlesex and State of New Jersey, have invented certain new and useful Improvements in Reflectors, of which the following is 'specification.

This invention relates to reflectors for use in apparatus for motion-picture projection and other purposes, and is especially useful in effecting the reflection of light rays from an incandescent electric lamp through a condensing-lens on a moving-picture film or other object orimaterial to be either illumi-' nated or subjected to the action of reflected light rays passed through a condensing lens.

WVhile the present invention is an improvement in reflectors, yet as they are of a special character of great and novel utility in special if not all uses, I set forth my present invention in an; apparatus and in cooperating relations to other things in order to show forth clearly the merits of the present invention. Said apparatus is not herein claimed, as it forms the subject-matter of my application Serial No. 217,083 of even date, filed Feb. 1 1, 1918, on which Patent No. 1,286,269 was granted December 3, 1918.

The .objects of the invention are to conserve and utilize a maximum quantity of light emanating from an incandescent electric lamp; and to produce a reflector of high efficiency and economy for use in motion-picture projecting machines; or for use in treatment of any material or object requiring exposure or subjection to light rays which travel from a source oflight through any suitable condensing lens. As I do not know all the industries in which my reflector may be practically useful, I take pains herein not to limit my invention merelyto use in motion-picture projecting machines, which use however is one that I have given particular attention to and onein which the invention is considered to be of very marked advantage'.

In the accompanying drawings forming a part hereof and illustrating the principle of this invention in the best mode now known tome of'applying that principle,

- Fig. 1 is a central lengthwise vertical section of the preferred form ofapparatus in which my new reflector is installed when it is used for motion-picture projections;

Fig. 2 is a front'end, and

Fig. 3 a rear end elevation, and

Fig. 1 a side elevation of the preferred form of the zone-shaped reflector removed.

Assuming that there is used in apparatus containing the present invention, a T-20 bulb, 600 watt, 2() ampere, 30 volt, Mazda C lamp such as is well'known for projection service; also that such lamp has a maximum efficiency of about 1.2 candle power per watt, or 720 candle power in all; also that a suitable condensing lens is used; and that in operation with the incandescent filament there is also used a suitable concave reflector back of the lamp and an outwardly-flaring faceted reflector that is approximately concentric with the point of light which is forwards of the concave reflector, the outwardly flaring reflector having its large end extending towards the condensing lens; and assuming also that the reflecting facets are 76 in effective number as herein shown in the preferred form of the outwardly-flaring .reflec tor, and that each such facet reflects an image of the incandescent filament which is also reflected in the concave mirror,--we have the following approximate results:

The point of light in operation with the concave reflector will yield about 80% of the candle power of the lamp, or 576 candle power. And each facet reflection will yield about 10% of the candle poweryielded by the point of light in operation with the concave 1nirror,-or 7 6 times 10% of 576, which equals 137 7 .6 candle power. The latter being added to the candle power yielded by the point of light from the concave mirror, gives a total candle power reflected through the condensing lens of about 4953.

Such a theoretical total useful candle power so obtained is comparable in ultimate effect with that often obtained by the use of an ordinary arc lamp; makes it possible to substitute incandescent for are lights in motion-picture outfits in many installations and with important advantages as regards safety, I

My new reflector comprises in its pretom opening of the zone-shaped reflector subtends about 64 of the surface of a sphere, and the width of the annulus from its smaller end to its outward end measures about 43 along thecircumference of the sphere. Preferably the larger end ofthe zone-shaped reflector is provided with a forwardly-extending conoidal rim the inner surface of which is at an angle of 25:1- to a tangential line parallel with the axis, the rearward spherical and the forward conoidal portions being preferably integral and together having a surface measurementcorresponding to 180 along the surface of a sphere.

-Referring to the drawings, 1 is a supporting frame 'or casing shown in a form com monly known as a lamp house; 2 an incandescent electric lamp bulb having a threaded socket member 3 which screws into a vertical interiorly and exteriorly threaded socket member 4 that is lengthwise adjustable in a collar 5 fixed to the upper wall of the lamp house concentrically with a hole through the wall. The lamp filament is indicated by 7. Forwardly of the lamp at a proper distance understood by all skilled in the art, the lamp house is provided with a forwardly-extending lens tube 8 wherein is placeda duplex condensing lens comprising in the preferred form of the invention a pair of plano-convex lenses 9, 9 spaced apart with their convex sides opposed. The long axis of the lamp is at right angles to the principal focal axis of the duplex condensing lens, or what is the same thing, to the axis of the lens tube. The inner side of the bottom wall ofthc lamp houseis provided with a lengthwise-extending dovetailed groove forming a guideway 10 parallel and opposed to a prolongation of the axis of the lens tube; The upstanding support 11 of a forwardly and outwardly flaring tubular reflector which in its preferred form is the annular spherical zone-shaped reflector 12 hereinafter more particularly described, has a dovetail foot 13 which fits slidablyin the dovetail guideway. The support ll has a hole through which the front end portion ofan adjusting IOdll is loosely mounted and held inplaceby a head 15 at thefront and acollarldat the rear side of the support; The adjusting rod is rearwardly threaded at 17 and passes through a thread ed'boss 18 in the rear end wall of the lamp house exteriorly of which it has a knurled headvl9z1 Back of the-annular, spherical the condenser lens tube is perpendicular.

This parabolic reflector is held in a crosssectionally round support 21 to the back side of whicha rearwardly-extending adjusting rod 22 is fixed, the rod being rearwardly threaded at 23 and passing through an interiorly-threaded boss 24: fixed in the rear wall of the lamp house exteriorly of which it has a knurled head 25. When parabolic reflectors having perforations through which lamp sockets are inserted are used, a loss of reflected rays occurs.

The diameter of the parabolic mirror support 21is slightly'less than the interior dia'meter of the rear end opening 26 of the annular spherical zone-shaped reflector, and theparabolic mirror may bemoved in and out through such opening 26 for the relative adjustment of the reflecting surfaces of the parabolic and zone-shaped reflectors. Rel-l atively to the filament orpoint of light, theZone-shaped reflector is adjustable by'the screw 14 and the parabolic mirror is adjustable by the screw'23', the filament being adjustable to the principal focal axis of the condenser lenses by the threaded socket member 6 in the fixed collar 5.

The lamp house is desirably ventilated by means ofanair-pipe 27 the discharge end of which is adjacent the metal lampsocket members within the chamber of the lamp house, the upper wall of which is provided with an air-escapeport '28 between which and the discharge end of the air-pipe the socket members are located. Exteriorly of the lamp house the air pipe is provided with a fan 29 which draws exterior air into the pipe and forces it into the metal socket members, the ,cooling current thus" set up entraining air within the chamber and. forcing it through the escape port. The parabolic reflector casing and both reflectors are out of contact with thelamp house walls. The parabolic reflector and the interior wall of the zone-shaped reflector are each'out of contact with the lamp bulb, and the front brim of the zone-shaped reflector is formed with an edge recess 30 whereby thezone shaped reflector atits larger front end can be-positionedrelatively to the filament. or point of light, with the edge .wall of the recessBO preferably out of contact with the socket member of'the lamp. Thus' air spaces are obtained between the reflectors, the lamp,'and the lamp house walls, and the rising hot air within the lamp house chamber and around the reflectors and the lamp is entrained by the forced air current at the top of the chamber, andforced out through the port 28. Overheating of'the lamp house chamber resultsin 1 undue shortnessof lif of electric'lamps therein andalso tends to impair the silvering of the reflector backs or exterlor surfaces when the reflectors are of silvered glass. I

What I have above termed an annular spherical zone-shaped reflector is a most important feature of my invention, but while formor shape is of the essence of its utility,

I do not wish to be understood from the following particularity of description as i11- tending to limit my invention in any degree beyond what the state of the prior art may legally require; and I point out that the i the parabolic reflector are separate reflectors as above described, the annular zone-shaped I reflector'is primarily anexteriorly spherical zone measuring (Fig. 4) about 43 from a at' its smallest diameter to b at its largest diameter; theopen .smaller rear opening of the reflectorlbeing subtended by an arc of 64 as indicated by the concave or parabolic mirror. The larger front end of the reflector ,3 forward of the diameter at b has an out wardly flaring integral conoidal brim 31 the outer face of which is at an angle of 252; to a line tangent to the point b, and the width of this angular or conoidal brim from 6 to c is such that the annular zone-shaped reflector as a whole is an approximate hemi, sphere in the sense that the front edge of the reflector as a whole is at the diameter of a sphere. I V Both surfaces of the conoidal brim 31 and of the spherical zone-shaped portion of the reflector are preferably formed with a plurality of rows'of flat-faced reflecting surfaces 01' facets 32, each rowlextcnding from the smaller end of the reflector to the out ward edge of the. conoidal brim. The exterior facets in each annular series are at an angle one to the other, and the exterior facets of the same series are also at an angle one to the other, and the facets in each exterior and each interior annular series are severally at an angle to an adjacent facet in one or more other series. 1 As shown there are fourteen rows of five complete facets each, and two rows of three complete facets each, four facets being practically lost by the cut-out forming the edge recess 30.

This annular flaring reflector, if made of glass silvered on its exterior surface, is made of one piece of glass to prevent the refraction which would occur at the lines of angular departure of one facet from another if the facets were made of separate pieces abutted edgewise t g ther, It is pra t c lly important. to make such flaring reflector of one piece of glass, and 'I have found that the same can be practically manufactured at low cost with the exterior and interior series of angularly disposed and opposed facets. It is also practically important that the elec tric lamp should be contained within the chamber of the annular flaring or zonal reflector, and this means that such reflector must have a recess in its brim for reception of the lamp socket if the most effective conservation of light rays is to be effected in motion picture projection and photographic enlargementor other operations.

The lines 00 indicate reflected light rays that pass, in parallelism through the condenser lens and then converge at a focal point at the center of the usual objective lens 33* after passing through a film positioned at 34 as usual in motion picture projection. Y

If the reflecting surface of the reflector brim were either in the arc of the circle of the spherical portion of the reflector, or curved inwardly, numerous rays instead of being reflected into the condenser lens as shown, would not pass properly through the condenser lens. 'But the brim may be omitted although it is economically desirable to retain it for the conservation. of all the rays that by seeming possibility can be conserved for passage in parallelism through the condenser lens. p i Y Various changes can be made from'what are set forth above as different forms of my invention, without departure from it. 7

Some important advantages of my new spherical zone, reflector independently of its integral brim, and when combined with a parabolic mirror and incandescent lamp are the apical junctions of the adjacent integral facets 32, which junctions are indicatedby the lines 33 which severally extend from the smaller back opening ofthe spherical zone reflector to its larger front opening, are severally continuous in a straight line. each being at the apex of a series of interiorly acute and exterior-1y obtuse, annular-ly-disposed adacent integral facets; the series of facets be tween any two of the lines 33 being severally trapezoidal when viewed in plan, and successively increasing in length from the smaller end to the larger end of the reflector; that is. the location of the facets is not such as to bring the ends of any trapezoidal facet in an annular series thereof between the ends of a trapezoidal facet in an adjacent annular series and thereby create such a multiplicity of irregularly-disposed angularly-ar ranged facets as would cause the light rays reflected from the glowing images in some of the facets to interfere unduly With light rays emanating from glowing images in other facets. By my integral structure of the facets I avoid th e of all interiorly circularribs of any material, such ribs if of metal interfering with the reflection, and if of glass causing, light-ray aberration. The facets of my spherical zone'reflector are not panesof silvered glass set in a framework as. heretofore. They. have reflecting portions of equal intensity and it is the main object of this invention to produce a one-piece interiorly and exteriorly facted' glass reflector wherein .the facets are reflecting portions of equal intensity and have no edge portions eX-. posed 'to the'light rays, but surface portions only, the interior'of the spherical zone reflector being free fromall light-ray-aberrationcausingjoints walls and :ribsso that it becomes in use as it were uniformly incandescent: a

What I claim is:

1. 'As a new article of manufacture, an annular reflector comprising a spherical zone and a therewith-integral outwardly fiaring iconoidal brim, the exterior and in terior surfaces being: each formed with a plurality. of annular series of facets which areangularly. disposed one to another; the

facets in eachannular series being severally angularlydisposed to a facet in a contiguous series; andthe spherical zone portion of the reflector measuring abo1it43 from its least to its greatest diameter; and its smaller end openingsubtending an arc of about 64; the integral facets being of trapezoidal shape and the angularly disposedadjacent ends of thefacets in-each series merging in a continuous apical line-from the smaller end opening to the larger end opening of the spherical zone, and the facets being of equal reflecting intensity: 7

2; In the-structure'of claim 1, an imperforateparabolic reflector at the smaller end of the annular reflector; the brim of the latter having a lamp socket receiving space; an incandescent electric lamp; and combined with the reflectors, lamp and its socket, means for adjusting the, reflectors one in relation to theot-her; and means of adjusting the lamp relatively to the two reflectors.

3. A spherical zone reflector, of one piece of suitable materialpthe interior surface being formedwith a plurality of annular series of trapezoidal facets which are angularly disposed one to the other in each lseries, each facet in each annular series being angularly disposed to a facet ina contiguous series, each inward facet being opposed to acorrespondingexterior facet, andsaid faceted surfaces beingrof like re flector construction, jointless, free from projections, and continuously smooth, andsaid facets merging directly and integrally one into another. at a projectionless angle, the facets inieach annular series reflecting the filament when incandescent; in combination with a fixture for holding an incandescent lamp with its filament Within the chamber of the reflector and such lamp;'thesaid spheri-f cal reflector having an outwardly flaringintegral reflector brim atits larger'end, and

the brim being formed with an incandescent lamp, receiving, opening; and a parabolic reflector at the smaller end of thereflector. I

,4. "A spherical zone reflector of'one piece of suitable material, the interionsurfaces being, formed with" aplurality .of annular serialof trapezoidal facets which archangularly disposed one to the other in each series,each facet in each annular series being angularly disposedto a facetlina co'ntigu ous series, each inward facet being opposed to a correspondingexterior facet, andsa'id faceted surfaces bein 1 of like reflector construction, jointless, ree fromprojections, and continuously. smooth, and said facets merging directly and integrally one into another at a projectionless angle, all the facets in each annular series reflecting the filament when incandescent; inicomb'in'ation with a fixture for holding an incandescen -t lamp with its filamentwithinthe chamber ofthe reflector; said rcflector h'aving a rigidexterior support movably mountedin a guideway; said guideway; andfsuch lamp.

In testimony whereof I have hereuntoset my hand this 9th day of February, WILLIAM VINOENT FoLE Y.

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