US2298308A - Light projector for motion pictures and the like - Google Patents

Description

S. PARISH Oct. 13, 1942.

LIGHT PROJECTOR FOR MOTION PICTURES AND THE LIKE File'd Feb. 4, 1939 INVENTOR. SCOTT PARISH AFFORNEY Patented Oct. 13, 1942 OFFICE LIGHT PROJECTOR FOR MOTION PICTURES AND THE LIKE Scott Parish, Cleveland, Ohio, assignor to All- Around Reflector 00., Cleveland, Ohio, a corporation of Ohio Application February 4, 1939, Serial No. 254,681

4 Claims.

This invention relates to motion picture projectors and the like, but has reference more particularly to devices for projecting the light through the film and to reflectors associated therewith.

Motion picture projectors and the like have heretofore been provided with parabolic reflectors which are designed to reflect light from a suitable source and to project such light through the film. Although such reflectors are usually 1 so positioned as to permit fairly satisfactory ventilation of the bulb containing th light source, they are inefficient from th standpoint of utilization of the light rays from th light source.

The present invention, accordingly, has as its whereby the bulb or other source of light with which the reflector is adapted to be used can be easily and efliciently ventilated.

Another object of the invention is to provide an incandescent bulb in which is incorporated efficient reflective means.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawing and the following description setting forth in detail certain embodiments of the invention, such disclosed embodiments constituting, however, but a few of the various forms in connection with which the principle of the invention may be used.

In said annexed drawing:

Fig. 1 is a front elevation of a preferred form of the device:

Fig. 2 is a side elevation of the device shown in Fig. 1;

Fig. 3 is a front elevation of a modified form of the invention; and

Fig. 4 is a view partly in section and partly in side elevation of the bulb shown in Fig. 3.

Referring more particularly to Figs. 1 and 2 of the drawing, it will be seen that the device comprises a base or socket I, formed of Bakelite or like material, and in which is mounted a transparent tubular incandescent bulb 2 having a source of light in the form of filaments 3 and 4 disposed therein adjacent the axis of the bulb.

Secured to the base I is a collar 5 having diverging circumferentially spaced bracket arms 6, upon which is supported a hollow spherical reflector 1 having circular openings 8 and 9 therein at diametrically opposite points and through which openings the bulb 2 extends, the openings being of slightly larger diameter than the external diameter of the bulb. Extending from the reflector 1 from a point adjacent the opening 9 is a flared skirt I0 which i preferably formed integrally with the reflector, and which serves a purpose to be presently described.

The reflector 1 also has a circular opening ll therein, the axis of which is normal to the axis of the bulb 2 and the openings 8 and 9.

Light rays from the filaments 3 and 4 are reflected by the internal surface of the reflector I which is highly mirrored and projected through the opening I I through suitable lenses, not shown, and thence through the motion picture film. It has been found that by the use of a hollow spherical reflector, such as th reflector 7, that there is an increase in screen illumination of from about 50% to about 75% over that of standard equipment now available on the market for this purpose.

In order to ventilate the bulb 2 sufficiently to avoid destruction of the filaments 3 and 4 as well as the film, the bulb 2 is cooled by means of an air blast, which, in the ordinary motion picture projector, is created by a fan which is disposed below the reflector and is directed against the bulb. Due to the provision of the flared skirt H) on th reflector, the air from such fan is caught by such skirt and is forced upwardly against the sides of the bulb, passing upwardly through the space between the reflector and the bulb so that the bulb is thoroughly ventilated.

The reflector l is preferably formed of sheet metal, and the inner surface is either highly polished or coated with a metallic substance which can be highly polished. If desired, however, the reflector may be made of glass and coated on either the inside or outside.

In that form of the invention shown in Figs. 3 and 4, the tubular bulb 2' is provided with filaments 3' and 4, which are disposed adjacent the axis of the bulb, and that portion 7 of the bulb which is adjacent these filaments is in the form of a hollow spherical segment, the internal surface I2 of which is coated with a reflecting material, such as silver, or other metallic plating, to provide a reflector for the light rays emanating from the filaments 3 and 6. The portion 1' of the bulb is flattened as at H to provide a window for the reflected light rays and this portion I I of the reflector is left uncoated. The window II is circular and its axis is normal to the axis of the bulb 2'. In this form of the invention, the bases of the reflector portion 1 are defined by openings 8' and 9 and the tubular portions of the bulb extend in opposite directions from these openings. If desired the outer surface of the reflector portion 1 of the bulb may be coated with a reflecting material instead of the inner surface thereof.

Since the entire outer surface of the bulb 2 is exposed, the bulb may be efliciently ventilated by directing the air blast against the reflector portion 1 thereof.

Other modes of applying the principleof my invention may be employed instead of the one explained, change being made as regards'the embodiments herein disclosed, provided the means stated by any 'of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. The combination of a tubular bulb having a light source disposed therein, and a member having a portion in the form of a hollow spherical reflector having spaced openings through which said bulb extends and a third opening having an axis normal to that of said first-named openings, said reflector portion adapted to reflect rays from said light source through said third opening.

2. The combination of a bulb having a source of light therein, and a member having a portion in the form of a hollow one-piece spherical reflector having openings therein at diametrically opposite points and a third opening therein having an axis normal to that of the other openings, said bulb extending through said diametrically opposite openings, and said reflector adapted to reflect rays from said light source through said third opening.

3. The combination of a hollow spherical reflector having openings therein at diametrically opposite points and a third opening therein having an axis normal to that of the other openings, and a tubular bulb extending through said diametrically opposite openings, said bulb having a source of light disposed therein and said reflector adapted to reflect rays from said light source through said third opening.

4. The combination of a hollow, one-piece spherical reflector having openings therein at diametrically opposite points and a third opening therein having an axis normal to that of the other openings, and a tubular bulb extending through said diametrically opposite openings, said bulb having a source of light disposed at the center of the reflector whereby rays from said light source are reflected through said third opening, said reflector constituting a relatively narrow band encircling the bulb intermediate its ends whereby both ends of the bulb are exposed.

SCOTT PARISH.

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