US2239784A - Rear projection screen - Google Patents

Description

April 29, 1941. J. a. HUDSON REAR PROJECTION SCREEN Filed April 25, 1936 d (LIGHT- DIFFUSIVE MATERIAL.)

INVENTOR JESSE a. HUDSON fonwwts UNITED STATES PATENT OFFICE REAR PROJECTION SCREEN Jesse B. Hudson, Philadelphia, Pa., assignor to Trans-Lux Corporation, New York, N. Y., a corporation of Delaware Application April '25, 1938, Serial No. 204,139

3 Claims.

My invention relates to a rear projection screen, i. e., a screen of the type wherein the projecting light beam passes through the screen while passing from the projector mechanism to As one example of a substantially transparent coating medium which yields satisfactory results in accordance with my invention, a satisfactory formula is set forth as follows:

the auditorium area or the like. 5 Parts by Volume In accordance with my invention, there is Lulseed 80 produced a. screen of the rear projection type h w O11 4 which comprises an oiled fabric suitably treated Flsh 2 to render the same properly light-diffusive for r (manganese dlqxlder cobalt OXlde, lead the intended purpose. I etc) 3 Further objects, advantages and characteris- Plasticlser (tn'cresyl phosphate tn'phenyl tics of my invention will appear from the followphosphate) 1 ing detailed description. 5 My invention resides in the rear projection Cellulose esters 5 screen, the method of producing the same together with f atu e of procedure of the The linseed O11 (boiled) has the other formula character hereinafter described and claimed. ingredients mixed thfirewith and then, in Suitable For an understanding of my invention and for manher h by dippmg tamy h an illustration of one form thereof, reference is fabrfc f a h formhd fljom h Coatmg to be had to the accompanying drawing, in which h sald coating medlum 1S aipphed to the the figure is an enlarged Sectional View Showing fabricafter the latter has been s zed. I Therea Screen as constructed in accordance with my after, in suitable manner, the fabric ,f is maininvention tained taut usually for many hours so that the In accordance with a preferred form of my coating F h may harden Set and, if necesinvention, there is produced a structure S of thls actwn may h hastened by Placing the sheet-like character having the function of servtaufly held treatfiid fab! in a heated a431105111191"?- ing as a screen or u f f h display of After the coating medium has set to a desired projected images. The aforesaid screen or surhxtent f Whlle 1t 15 515.111 Somewhat tacky, the face is disposed, usually, substantially vertically l -q s g 1n accordance 11th the between the auditorium area and the projector 1S ahphed F h coated fabric Surfacemechanism, the beam of light from the projector To thls hght'dlffuslve matfirml d Such as nechanism passing to the auditorium area after corn starch talcum powder, Z1110 Oxide, Zinc t traverses Said screen or u f c stearate, titanium oxide, or the like may be A screen or surface constructed in accordance evenly distributed as by sprinkling; an blast 1th my invention may be produced in a variety operation, or the like on such coated fabric surf ways. 'Ihus as a coating medium for suitable face. The amount Of the light-diffusive material ,bric f such, f r example, as natural silk, artid which is thus utilized is dependent upon the .icial silk or other suitable material, it has been light-transmission factor w h t e completed demonstrated that there may be utilized a more Screen is to have although, i ene al. it will be or less transparent mixture formed principally understood that the q y f Sa d1i htdifiu from linseed 11 t which is combined other sive material d is such that the screen diffuses suitable oils and ingredients such as cellulose lightin a proper a er When it is included esters, synthetic resins and plasticisers as desired. in a rear p ojection system. After t Screen fabric in t m manner, r After the light-diffusive material d has thus has had applied thereto a coating of the charb en applied all at one time or by successive acter described and, after such coating had dried p ns o o e Or both faces of the coated t it bl t t th i applied t' th t d fabric 1, the latter is maintained taut until com- I fabric surface a medium (1 utilizable as a light p ete y dry whereupon it may be cut to form diffuser. screen sections of a desired size. The screen.

sections may be suitably bound at their edges,

assembled in their respective frames.

when a fabric is coated as described above,

the oxidizing oil, in addition to its desirable the screen despite the above noted tendency of the oxidizing oil.

The use of fish oilas a part of the coating medium is desirable because it serves somewhat as a plasticiser to cause the completed screen to be relatively flexible and pliable.

Under some circumstances, to incorporate other oils or materials in the above described coating medium. Thus, it may be desirable to include in said coating medium a small quantity of Perilla oil which, somewhat the same as the Chinawood oil,-causes the coated surface to be tougher and to more readily take the subsequently applied light-diffusive material. soya bean oil may be incorporated in the coating medium, such oil serving to restrain the treated'fabric I from turning yellow. Also, as generally stated above, it may be desirable to Further, if desired, a small quantity of it may be desirable add to the coating medium one'o'r more cellulose eithers such as ethyl cellulose or one or more cellulose esters such as cellulose acetate, etc. and alsocertain organic synthetic resins.

It is to be distinctly understood that my invention is not to be limited to the formula herein described in detail since it will be understood by those skilled in the art that the proportions of the specified materials may be varied within reasonable limits and, moreover, some of the specified materials may be omitted and others supplied, if desired, to thereby produce a coating medium having desired characteristics.

While the invention has been described with respect to certain particular preferred examples which give satisfactory results, it will be understood by those skilled in the art after understanding the inventiornthat various changes and modifications may be made without departing from the spirit and scope of the invention audit is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new and desired to be secured by Letters Patent is:

.l ng by said coating medium being a to the coated surface of as well understood in the art, before they are 1. A rear projection'screen comprising a fabric she t, a coating medium mixture comprising linseed oil principally together with Chinawood oil and fish oil to considerably less extent, said coating medium, after application to said fabric sheet, causing the surface thereof to be in tacky condition, and powdered light-diffusive material applied externally to the-coated surface of said fabric sheet, said light-diflusive material serving to overcome the tacky condition of said fabric sheet, said light-diffusive material and said fabric sheet serving to diffuse the light ofthe projecting light beam while permitting the passage of suflicient light for rear projection practice. I

2. A rear projection screen comprising a fabric sheet, a coating medium' for said fabric sheet, said coating medium being a mixture comprising linseed oil principally together with Chinawood oil, fish oil, soya bean oil and Perilla oil to considerably less extent, said coating medium, after application to said fabric sheet, causing the surface thereof to be in tacky condition, and powdered light-diffusive material applied externally said fabric sheet, said light-diffusive material serving to overcome the tacky condition of said fabric sheet, said lightdiflusive material and said fabric sheet serving to diffuse the light of the projecting light beam while permitting the'passage of sufficient light for rear projection practice.

. 3. A rear projection screen comprising a. fabric sheet, a coating medium for said fabric sheet, said coating medium being a mixture comprisvolume linseed oil principally together with about three parts of a dryer, substantially less than three parts of a plasticiser, Chinawood oil, a 'resin'and a cellulose ester eachapproximately in the same proportion and each somewhat greater in volume than that of the dryer, and fish oil in volume somewhat less than that of the dryer, said coating medium, after application to said fabric sheet, causing the surface thereof to be in tacky condition, and light-diffusive material applied exteriorly to the tacky coated surface of said fabric sheet, said lightdiffusive material serving to overcome the tacky condition of said fabric sheet, said light-diffusive material and said fabric sheet serving to diffuse the light of the projecting light beam while permitting the "passage of suiiicient light for rear projection practice.

JESSE HUDSON.

for said fabric sheet,

Images