US2278073A - Projection screen - Google Patents

Description

M r h 1 942 T. s. HARKNESS 2,218,073

FRO-TECTION SCREEN Filed Jan. 20, 1959 fmrezz for THO/7A5 3/1 Muck/v5.55

* gym Patent ed Mar. 31 1942 v 2,278,073 PROJECTION SCREEN Thomas Smith Han-knees, London, England A pplication January 20,

1939, Serial No. 251,895

In Great Britain July 25, 1938 1 Claim. (01. 88-24) 7 being incombustible, are not so easily transported and erected as cloth screens.

One object of the present invention is to provide an improved projection screen.

Another object of the invention is to provide projection screens for talking motion picture reproducing systems which are both incombustible.

A further object of the invention is to provide an improved method for. the manufacture of projection screens.

The screens are made by perforating a sheet of wire gauze of small mesh to provide for the passage of sound therethrough and then spraying the wire gauze with a surfacing composition at a pressure to fill in the meshes of the gauze but to pass through the perforations.

The predominating material of the screen, at least on the projection side thereof, may be the surfacing composition or paint, the wire gauze or the like serving merely as a carrier for this material which may completely cover the wire gauze on the projection side of the screen so as to provide a smooth projection surface. The surfacing composition is preferably of a substantially fire-proof nature and provides the required white or light-coloured picture projection surface and also imparts pliabllity or suppleness to the screen so that it may be stretched in position and otherwise handled in substantially the same way as a screen of textile fabric.

A convenient metal fabric to employ is '10 mesh gauze of 38 gauge soft phosphor bronze wire. This gauze is perforated and then coated with a surfacing composition or paint, which may consist of a pigment, such as barytes and zinc oxide, together with appropriate oils and solvents and a small proportion of cellulose material. Alternatively, the metal fabric may be coated with water paint or distemper to provide the picture projection surface. This material has the advantage that it can be readily washed off or otherwise removed when the screen becomes dirty, and a fresh coating applied.

pliable and The surfacing composition or paint may be sprayed onto one side of the wire gauze. The resulting screen has a smooth white surface on this side and can be bent and also stretched in position in substantially the same way as a textile fabric screen. The screen is provided with aperample by means of a perforating machine, and has substantially the same surface appearance and can be handled in the same way as a textile fabric screen, but has the advantage over the latter of having the combustible textile fabric replaced by an incombustible metal fabric. The apertures may for example consist of rows of circular perforations of about inch diameter located about inch apart. As the perforations are formed in the screen before it is coated, the coating should be-applied in such a way as not to fill in the perforations. It has been found that if the surfacing composition or paint is sprayed on at a pressure of 40 pounds per square inch it will not fill in the perforations.

Several sections of coated metal fabric prepared as indicated above may be joined together side by side in the same way as the sections of a textile fabric screen, for example by sewing together their adjacent edges. The sections of metal fabric may also be joined by securing their adjacent edges together by means of clips or by welding or fusingthese edges together. A suitable method of welding together the sections of metal fabric i disclosed in British Patent No. 350,541. This method of welding provides a smooth seamless join which is invisible from the front of the screen when the surfacing composition has been applied. The perforations may be provided in the sections of metal fabric first, then the sections may be welded together, the wire screen so formed erected'in position, and, finally coated in situ with the surfacing composition or paint. The screen may be stretched and hung in the same way as a textile fabric screen.

A front view of a small portion of a projection screen according to the invention is illustrated in the accompanying drawing, the surfacing cornposition being removed from part of the screen in order to disclose the wire gauze support. In the drawing the' reference I designates the surfacing composition which forms the picture projection surface and the reference 2 designates the wire gauze sheet to which the surfacing composition is applied, the perforations in the screen, which extend through both the surfacing composition and the wire gauze support, being desigperforations in each row being staggered or dis- Other metals or alloys which provide a relative] placed in a. transverse direction with respect to soft or flexible fabric may also be employed those in the adjacent rows Any other sym- 5 at is claimed is:

metrical distribution of the perforations may be A method of fabricatlon of projection screens

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