US1915842A - Illuminating apparatus - Google Patents

Description

June 27, 1933. 7 F. c. WINKLER I 1,915,842

- nnuummme APPARATUS Filed Oct. '29, 1932 WITNESSES: INV ENTOR 4 Fae: GM'n'K/er.

ATTOR Y Patented June 2 7, 1933 fUNlTED s'm ras PATENT ornca FEEDING C. 01 LAKEWOOD, OHIO, ASBIGNOB T WESTINGHOUSE nmro & MANUFACTURING COMPANY, OF EAST PITTSBURGH, IENNSYLVANIA, A CORPO- BATION OF PENNSYLVANIA mumarmo mmrus application med October 2a. 193:. mm no. 046,175. I

My invention'relates, generally, to illuminating apparatus, and, more partlcularly, to I reflectors of the ty e suitable for use 1n connection with flood lighting units.

' The object of my invention generally stated is the provision of a reflector which shall be simple and eflicient in operation and which" ma be economically manufactured.

1 more specific object of my invention 1s to provide for causing a reflector to produce an evenly distributed projected beam of light.

Another object of m invention is to rovide for eliminating fi ament striation's 1n a specular reflector.

A further object of my invention'is to provide for causing a reflector to produce an evenly distributed rojected beam and a substantlally perfect ade-out of the beam without filament striationsby means of stippling on the reflecting or pol shed surface of the reflector.

scription taken in conjunction with the acthe stip ling shown in Fig.- 1.

A still further'object of my invention is to provide a reflector having graduated symmetrical stipples on the inner or projecting portion and a large number of smaller sym-' metrical stipples unsymmetrically placed over the entire secondary reflecting or outer portion of the reflector. v

Other objects of my invention will become apparent from a reading of the following decompanying drawin in which; Figure 1 is a sectlonal view ofa reflector showmg a small'portion' of the stippling arranged in accordance with the invention, and

Fig. 2 is-an enlarged view of a portion of In re ectors of the type to which my invention relates, one of the most important features to be desired is to cause the reflector to produce an evenly distributed projected beam and a secondary beam havinga substantially perfect fade-out.

I have discovered that these features may be obtained by the use of properly arranged stipplingon the inner or reflecting surface of the reflector.

Another highly desirable feature in reflectors of this kind is to eliminate filament striations in the reflected beam caused by the reflection of the filament of the lamp or light source itself.

This'feature is especially desirable where high wattage lamps areused'. which do not have a point source of filament.

'Heretofore, filament striations have been eliminated by the use of a difi'using lens placed in front of the reflector or by imposing some sort of a diffuser directly upon the reflector or by using a frosted lamp.

I have discovered that the undesirable filament striations maybe efliciently and inexpensively eliminated by the use of a graduated symmetrical stipple. Since the .spread of the lamp filament is greatest-at the points on the reflector nearest to the lamp, the graduated stipple roduces the. desired even distribution of t e projected beam.

In view of the fact that the diameter of the reflector increases from the back of the reflector to the front or outer edge, the symmetrical arrangement of graduated stipples cannot be continued to the'outer edge of the reflector because the stip les increase to such large diameter as to rod sha d bands aroun of t e projected beam. Since only a certain portion of the reflector, usually about sixty to seventy per cent of'the back or inner portion, is utilized to project the main beam the graduated symmetrical stipples may be formed in this porti'on only in order to produce an evenly distributed main beam.

The cone-shaped bands may be then elimi-' nated and a substantially perfect fade-out the entire periphery produced by utilizing a diflerent arran Referring now to the drawing, the refer-; ence character 1 designates, generally, a re'-,

ucea series of cone;

e outer end of the flector which may be used in connection with flood lighting units of various kinds such, for example, as window flood-lighting units and the like.

In the reflector shown the curvature of the reflecting surface is such that the main beam of light from the source (not shown) is accepted by approximately seventy percent of the reflector at the inner or back end, the secondary beam being projected by approximately thirty ercent of the reflector at the outer edge. 11 other words, the seventy per cent portion is covered by the graduated symmetrical stipples 3 while the thirty per cent portion or outer band is covered with tlie small unsymmetrically positioned stipp es 5.

It will be readily understood that the ratio of the area covered by the small unsymmetrical stippling 5 and the area covered by the larger graduated symmetrical \stippling 3 may be varied to suit the size and shape or curvature of any particular reflector.

It is to be understood further that the small st'ippling 5 on the outer edge ofthe reflector may be also used with other than graduated symmetrical stippling on the main portion of the reflector and that the shape of the stippling is immaterial.

From the foregoing description, it will be apparent that I have provided for obtaining substantially ideal conditions of light distribution from a single reflector thereby making it unnecessary to use a plurality of flood lighting units to obtain an even distribution over .a fairly large area. Furthermore, a plurality of units employing reflectors embodying the novelfeatures of my invention may be used to obtain a very even distribution over a large area since there is no tendency for the building up of intensityover certain areas because of the desirable fade out distribution.

It maybe stated, in conclusion, that while the illustrated example constitutes a practical and economical embodiment of my invention, I do not wish to limit myself strictly to the exact details herein illustrated, since' modifications of the same may be made with out departing from the spirit of the invention, as defined in the appended claims.

I claim as my invention:

1. A light reflecting device comprising a concave member having an inner light refleeting surface formed with a plurality of protuberances thereon, said protuberances being distributed over the reflecting surface in such manner as to produce an even distribution of the projected main beam and a secondary beam having a substantially perfect fade out. i

= '2. A' light projecting device comprising a concave member having an inner light reflecting surface with a' plurality of p)reotuberances formed thereon, the prot r- .end of the reflector ances on the outer or open end of the concave member being smaller in size than the protuberances on the remaining portion of the reflecting surface,

substantially perfect fade out characteristics of the projected beam.

3. A reflector for projecting a beam of light comprising inner reflecting band of small uniform stipples at the outer a concave member with an surface provided with athereby to provide or open end thereof, the remainingportion of the reflecting surface being provlded with large non-uniform stipples.

4. A reflector for projecting a beam of light comprising a concave member having an inner reflecting surface provided with stipples thereover, the stipples on the part of the reflecting surface utilized for projecting the main beam being symmetrical and graduated in size and the stipples onthe part ject the secondary beam being smaller t an the largest of the symmetrical stipples, thereby to provide an even distribution of the main beam. and a substantially perfect fade out of the secondary beam.

5. A reflector for projecting a beam of light comprisin a concave member having an inner reflecting surface with a plurality of protuberances formed thereon, the pro- 'tuberances covering a ffpredetermined portion of the reflecting su ace being graduated in. surface area, the protuberances covering the remaining reflecting surface being uniform in size and having a surface area which is less than the surface area of the protuberances over the said predetermined portion of v of the reflecting surface utilized to roroe uated in diameter in accordance with the increasing diameter ofthe reflecting surface, the protuberances over the remaining portion of the reflecting. surface at the outer or open end of the reflector being uniform in diameter and of smaller diameter than any of the other protuberances. & Y 7. A light reflector comprising a concave or hollow member having an interior reflecting surface with a plurality of rows of convexities therein gradually increasing in size from the back of the reflecting surface toward the front or open end of the r flector over a predetermined portion of the surface, the convexities covering ther maining portion of the reflecting surface ear the open being 'of smaller size and uniform.

8. A light reflector wmprising a concave or hollow member having an interior reflectthe edge or open end remaining rtion of the reflecting surface being of uniform diameten.

In testimony whereof, I have hereunto subscribed my name this 20th day of October,

'FREDERIC C. WINKLER.

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