US1743602A - Projection screen for motion pictures - Google Patents

Description

Jan. 14, 1930. c. A. HARSON PROJECTION SCREEN FOR MOTION PICTURES Filed Nov. 26, 1929 Patented as re, lose UNITE crates arana lorries.

cnns'rnn'a. Han-son, or rarnwrosi', nessncnnsrlnrs, assrsnoa 'ro sansson n scanner comma, or nosrou, irassaonusnrrs, a. conronnrron or nsssaoansnrrs rnorncrron scnnnrr roa no'rrosr rrcrnans Application filed November 28, 1929. Serial Ito. 409,931.

'lhis invention relates to reflecting screens and-has particular reference to screens for use in motion picture theaters which employ so-called loud speakers behind the projection screens for the transmission of speech and projection screens so that they not only will properly reflect all details of the pictures but also o fier the least possible obstruction to the. transmission of sound of all kinds through the screens. 7

.One kind of material heretofore employed for projection screens is composed of canvas or duck fabric coated with aluminum and bronze. powders. Such material interferes with the transmission of sound. Another kind of material employed consists of cotton threads woven with suflicient looseness to permit the transmission of sound through the fabric. This fabric, however, does not reflect pictures entirely satisfactorily, and the large amount of soft cotton seems to absorb some of the sound.

Another kind of material proposed con-- sists of a fabric including metallic threads,

which fabric is rolled to crush the metallic threads, but such fabric is not well adapted for use in connection with what are blown as sound pictures, as it is too finely woven, and the crushed metal interferes with the transmission of sound.

Another kind of material proposed consists of all polished metal strands or wires of double convex form in transverse section, closely interwoven, but such material is too bright for many pictures, and interferes with the transmission of sound. I

@ne of the objects oi'the present invention is to provide an improved screen for the purposes explained, which screen presents a great multitude of very fine dots of material which aremade luminous by the rays of light from a motion picture projector and therefore efi'ect reflection of all details of the picture.

Another objectis to provide a satistactor reflecting screen that ofiers the least possible obstruction to the transmission of sound through it.

p With the above mentioned objects in view, and others hereinafter explained, the invention consists in the construction and com.-

bination of parts substantially as hereinvation of asmall portion of the reflecting screen fabric. v

Figure 3 represents a section on lined-3 of Figure 2. I

Figure 4c is a view similar to Figure 2 but taken from the rear of the fabric.

Figure 5 represents a section on line 5-5 of Figure 2; Similar reference characters designate similar parts or features in all of the views The fabric of my improved screen, of the specific Woven type illustrated by the draw- 'IIIgS, consists of weft and warp threads, one

or the series of threads consisting of rather soft fibrous material and those of the other series consisting of bright metal material, such as silver wire, the weaving being such as to cause the fibrous material to protrude between the reflecting material and storming protuberances of fibrous material larger than the infinitesimal areas of bright material, and the weaving being suficiently loose to permit the transmission of sound.

Referring first to Figure l, the fabric as a whole is indicated at 12, said fabric having bindings 13, preferably loop-shaped in transverse section, to receive rods 14 which, in

practice, have connected thereto means for stretching the fabric to very taut condition.

The important feature of my invention resides in the structure or composition of the woven fabric of the reflecting screen 12, said fabric consisting of warp strands l5 and weft strands 16. The warp strands 15 are ofvery fine bright reflectin material such assilver wire, while the welt strands 16 are or rather loose material such cot till ' are in front of the weft strands with the latter in pairs and running behind some 10, moreor less, of the weft strands 16 as illus trated by comparing Figures 2, *3 and 4:. And, as illustrated by Figure 5, the upper margin of which represents the face of the fabric and the rear marginof which figure represents the rear face of the fabric, the

- horizontal stretches of the strands 16 extend across six or seven, more or less, of the warp strands 15. The result ofthis structure or its substantial equivalent is such that, in use, the light from the picture pro'ector vstrikes small brightspots and is re ected onto the fibrous protuberances which materially exceed the bright material in front or face exposed area, resulting in so exhibiting the picture that such picture. is nearly as well viewed from an angular direction as from directly in front. This is because some of the light is reflected from the fine bright spots somewhat against the sides of the fibrous protuberances. I Y

A veryimportantfeature of my invention resides in the fact that the fine interstices of the fabric permit the un-mufied transmission' of sound to the audience from the usual loud speakers mounted behind the screen.

A further advantage resulting from the employment of the fine metal wire is that, due to its inherent'resonanc'e, the screen as a whole slightly vibrates in synchron'ism with the sound waves and therefore enhances the transmission of sound to the audience.

The present application is filed as a conwhich presents infinitesimal areas of bright,

metal with larger protuberances of soft fibrous material, said screen havin interstices to facilitate the transmission 0 sound.

screen having interstices to facilitate the transmission of sound.

between reason 4. A motion pictureflscreen of woven material,ithe strands extending in one direc tion being of fine reflective material and the strands which traverse said fine strandsbe ing larger and of soft absorbent material and presenting protuberances alternating with the fine reflecting material.

5. A motion picture screen having alternatin protuberances and depre'ssions,-the protu erances being composed of pairs of soft strands of fibrous material and'the de-' pressions presenting small bright reflectors. In testimony whereof I have aflixed my signature. V

CHESTER A. z:

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