US1491830A - Screen for picture projection - Google Patents

Description

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UNITED STATES PATENT OFFICE.

JOHN F. n; TnoEeEB, oF BnooxLYN, NEW Yonx, AssIGNolamr MEsNE ASSIGNMENTS, 'm rrnANs Lux DAYLIGHT PICTURE scnEEN', INC., A CORPORATION or DELAWARE SCREEN FOR PICTURE PROJECTION.

Application ined Nay 1e, i920. semi Na. $141,290.

. To all whom it 'may concern.:

Be it known that I, JOHN F. R. TxoEoEn, a citizen of the United States, and resident of Brooklyn, in the county of Kings and 5 State of New York, have invented certain new and useful Improvements in Screens for Picture Projection, of which the following is a specification. i

This invention relates to exhibition screens for projecting machines. The principal object of the invention is to provide a screen of the character described in my Patents Number 1,151,502 of August 21th, 1915 and Number 1,216,380 of February 20th, 1917, as they are well suited `for use with the present invention, and having certain ad vantages b reason of discoveries made by me since tl'lie filing of my former applications. contour of the corrugations formed in the display surface of the screen, to the number of corrugations per inch and to the color of the screen, it having been found by experience that the color is an important ele- 26 ment in the screen, as by employing a color com lementary to the color which is preferabIy blue of the projecting li ht a, perfect reproduction of the colors of t e picture as well as the black and white tones is secured 30 and the picture presented is much clearer and less tiring to the eyes of the observer.

It is also important where the picture is to be projected from behind the screen, to a person viewing it from the front side, 36 that the screen be made of a thickness and vtranslucency best suited to interptv the 1i ht and reveal the picture without transmitting direct rays or allowin the light from the projector to be seen t rough the 40 screen.

Referring to the drawings which form a part of -this specification, Figure 1 is a perspective view of a screen or curtain embodying my invention. a Figure 2 is a. slmilar view shown on an enlarged scale.

Figure 3 is an -end view illustrating the form of the corrugati'ons.

In carrying out my process to produce 60 the improved composition, I take four arts of gelatinous or gumm substance suc as -gelatin or glue and a d to the same two parts of glycerin and two parts of formal- My present invention relates to the -form of the corrugations.

dehyde and boil until water is driven off when a dough-like mass remains which ma be rolled into sheets. The latter, while sti l soft, ma be run over with a corrugated roller, w ich imparts to the surface of the sheet longitudinal corrugations or ridges. The sheet may then be dried in an oven or hot room at about 100F. The gl cerin imparts Hexibility to the base whi e the formaldehyde tends to harden the sheet and to make it insensible to changes in weather conditions in regard to temperature and humidity and also renders it fireproof.

` Thus, the screen may be used in the open air and not be affected by the elements and is also safe as a fire risk. Referring to the drawing A indicates the sheet of material and B-B etc., the corrugations formed in one side thereof and C indicates-the wave D indicates a median line drawn through the wave form.

I may vstate that the greater the number of corrugations used per inch of width, the better the screen will be up to the practical limit obtainable with the materials employed. In practice this limit has therefore been found to be about forty corrugations per inch.

I have found that thirty-two corrugations per inch of width gives very good results and that it is difficult to make the screens with more than this number and have them mechanically true in form, especially in*v screens of large demensions.

Referring to Figure 3, it will be seen that the wave-of the corrugation is erfectly sinuous. I prefer to use asinusoi al curve but do not wish to be limited to the use of this curve only.

It is obvious that my present invention may be used with screens other than flexible for screens of small dimensions. By using a screen as herein described, a picture may be viewed by a person sitting at 'an acute angle to the plane of the screen without the pictures appearing to be distorted. From any angle the diffusion of the light is sov even that the eyes of thel observer will not tire from -the effect of high lights.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. A screen of blue translucent material having sinusoidal corrugations in the display side thereof evenly disposed and numbeting preferably not less than twenty per inch.

2. A screen having sinusoidal corrugations formed in the display side thereof only and extendingy vertically, and evenly disposed over` the surface thereof and numbering not less than twenty per inch.

Signed at New York city, in the county of 10 New York and State of New York this 13th day of May A. D. 1920.

JOHN F. R. TROEGER.

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