US2403199A - Apparatus for forming evaporated films - Google Patents

Description

y 1946. J. E. SWOPE, JR., ETA; 2,403,199

APPARATUS FOR FORMING EVA PORATED FiLMS Filed Sept. 24, 1943 7 34 IO @x J 2.2 FIGL'I JOE E.SWOPE JR. ARTHUR F.TURNER f OSMAR A. ULLRICH JR.

Patented July-2, 1 946 S PAT APPARATUS FOR FORMING EVAPORATED FILMS Joe niswope, i s to Jr., Rochester, Arthur F. Turner, and, Osmar A. Ullrich, Jr., Roch-' ester, N. Y., assignors to Bausch & Lomb Optical Company, Rochester, N. Y., a corporation of New York Application September 24, 1943, Serial No. 503,696

This invention relatesto apparatusfor form ing films ofdistilled material's. I

A distilled film can be formed by vaporizing a film-forming material in an evacuated space adjacentthe body to receive the vapor. The film forming material has generally been either fonnedinto small U-shaped strips and suspended over-"a heating filament orthe film forming material has been held in a suitable crucible in heat receiving relationship with the filament;

I Thepracticeoi suspending thestrip of the film forming material' over the filament is practical where a relatively small quantity of the'material is to vaporized. Itjcannot be used where either a relatively'heavyfilm is to'be deposited or a relatively large surface is to be coated, unles the source be replenishedirom time. to time. This is not practiea1 ?1"lt necessitates the dismantling oi'the evacuated container to gain access'to the source and then pumping down the container after it has been again assembled and resuming the evaporation cycle.

5 Although a relatively large amount of film forming material can be evaporatedifrom' a crucible in heat receiving relationship with a file-. ment, considerably more input isrequired to heat the material, andthe heat may cause objectionable out-gassing of adjacent metal parts oi the apparatus. Furthermore, in some applications it is necessary to maintain a point source of material during the evaporation process,

The primary object of, the present invention is to provide means for vaporizing a relatively large quantity of film forming material without the heat of the prior crucible method and yet maintain a point source during the evaporation cycle. The means for accomplishing this feature of the present invention comprises means for holding 5 Claims. (Chill-12.2) I

v the base plate Ill by any suitable sealing means I 2. The bell Jar II is connected by some. con-.

an elongate member of the film forming materia1 in contact with the heating filamentfluntil the portion of the member in contact with'the heating filament becomes molten and forms a bead. We have found that, after the bead of molten material is formed, the member .will'not separate from the bead.- and that as the material oi the bead is vaporized, the member is drawn up into heat-receiving relationship with ithe'filament so that the moltenmass plenished as it is vaporized.

If it is desired to evaporate a larger quantity oi the material, a plurality of members can be mounted in a suitable carrier and seriately moved into contact with the filament to carry out the process. As a number of the members can is constantly rebe seriately vaporized, it is possible to deposit .is formed, the body of ing in which: Fig. 1 isan elevational .view, partly in section,

laminated films of different materials by form ing the members of the desired materials.

In a modified form of the present invention, I the film forming material can bei'ormed into a chain having a length longer thanthat length of member which can be vaporized-in the preferred embodiment of theinvention. In 'this form or the invention, the one endoi the chain is held in contact. with L Y the chain being supported adjacent th filamentand the chain vapor ized as in the earlier described form of thepinventlon. l,

Other features invention will be description taken and advantages of the present apparent from the following 01 the apparatus of the present Fig. 2 is an elevational view film-forming material. I 1.

Fig; 3 is an enlarged fragmentary. view showing a portion of the heating filament and themolten mass of the film-forming material.

invention.

Fig. 4 is aperspective view of the carrier bf the apparatus for holding a plurality gated piece of film-forming'material.

Fig.5 is a view of a modified form of the apparatus'oi thelpresent invention. The apparatus of the present invention, referof the elon ring now to the drawing, comprisesa suitable base plate l0, which supports an evacuable contalner shownflhere as a bell jar ll of glass or A vacuum-tight seal is formed 7 other material. between the lower edge of the bell jar II and ventional means, such as the pipe 13, to a high upward from the base plate Ill and earryatithe upper endthereof 'a support It which, in the form of the apparatus now preferred, comprises a plurality of concentrically arranged annular of the support members. The outer member I! fixed tothe upper'end of the stanchion I! in anyv manner desired ,..i fo'rmed with a seat on which is removably mounted an annular flange oi, the

inner member I8. The innermember i8 is like-. wise {ormed 'with a seat such as the seat of-thev outer member, and which can be used to concentrically .mount a plate IS, the underneath surface of which is'to receive the film of distilled material.

In'the illustrated form of the invention, the

the filament until a bead;

in connection withythe draw of one form of the,

iforming .material was formed into small U- material to be evaporated is heated by a heating filament 2| carried by current-conducting posts.

22 supported in 'thebushlngs 23 of insulating material fitted into aperture formed in the base plate It. The heating element 2| is connected to a suitable source of current, not illustrated in the drawing, through lead-in conductors 24. Inone widely used prior: practice, the

clung to the filament until the material was completely evaporated. This technique could be used only where a small amount of material was f I to be evaporated, and if a larger quantity was desired, it was necessary to place the material in asuitabie crucible placed in heat-receiving relationship with the'fila'ment. Although thisfltechnique permitted a larger amount or quantity of the material to be eva or ted. lt ha'd itslimitations'and could not be'used where, it wasfnecessary in thepro'cess to have the vapor emanating a i from a point source.

--The present invention provides means for 1 4 ing material are supported by a suitable carrier comprising upper and lower semi-circular plates 29 and 30,- respiectively. The plates are spaced apart by a strip 3| whichcan' be formed integral with the upper 'plate 29-and bent down and se cured to the one edge of the lowerplate by any means desired. The upper plate 29: is formed with a plurality of apertures 32 equally spaced from the center of curvature of the plate 29. The apertures have a diameter greater than the diameter of the rods 28 and are in alignment with sockets 33 formed inthe upper fa'ceof the lower. plate 3|). It will be seen; referring to Fig.4, that the rods 28 can be supported in the carrier by passing each rod through an aperture 32 until the lower end thereof is received in the socket 33. .The carrier is rotatably mounted on the base I plate I0 through a shaft 3l -rotatably supported evaporatingja large quantity of the film-forming material and yet maintain substantially a point. 1

process; In carrying on the process ofthep'ressource during the entir}evaporation cycle of the ent inv'ention,.the film forming r'naterial can be, 3 formed into an elongate member-or rod 26 and, preferably, the one'end oi the rod is. formedwith. 1

a. small hook2'l to permittherod to be suspended,

from the filament 2|.

We have found that theportlon oi thejrodin j contact with'the filament will melt and vform-a easily predetermined value, will notseparate bead as in'the prior practice and that the rod, 1 if'the' mass weight thereof is kept below some 5 as best shown in Fig. 3. It will be understood that the film-forming material'must wet" the j filament, forotherwise the bead will not cling to j the filament.

The end of the rod not only is held tothe'bead but will be pulled up into heat-receiving relation- 1 ship with the filament as the mass of the material forming the bead vaporizes.

. The size of 'the rod which can be used will, of

course, depend upon the materialof which the 1 rod is formed and the specific gravity or the same,

I'nconelfif comprising 79.5% nickel, 13% chrof orated by the method herein disclosed. As'the, end of the rod adjacent the filament melts, the. head is replenished andthe'evaporaj mium, and 6.5% iron, can be successfully evap-g tion cycle can be carried on until the rod is comsacrificing the. advantages of a point source.

If a'larger quantity of material is desired'to be evaporated, a plurality of rods can be formed and pletely evaporated. 1 Thus, a relatively large 1 quantity of material can be evaporated without the 'rods successively vaporized. can be accomplished without dismantling the bell jar by supporting the rods in such a manner that each rod can be moved into contact with the heating filament as the vaporization of the preceding rod 1 is completed.

I In the embodiment of the present invention illustrated in Fig. '4, the rods 28 of the film-formby a plurality of dry bearings 35 mounted within a well 36formed of somenon-magnetic material. It will thusbe seen that the carrier ,is rotatably mounted for movement about the longitudinal axis of the shaft 34 which. passes through the center of c'urvature of both ofithe plates. The shaft. carries an jarmature 3 at thelower end thereof and as-the well 35 is formed of some non magnetic material, the carrier can be moved into any desiredadjusted position by moving the mag-.,

net 38 held adjacent the lower wall of thwell;

In carrying out the process where a plurality of rods 28 are to beevaporated, after. the carrier has been placed within the container and the.

same evacuated, the filament. 2| is energizedand the carrier moved to bring one of therods28 into contactwith the filament 2| Thefilam'ent should be so disposed relativetoj the rods that as each rod is moved into engagement with the filament, the same will contact 'eachrod at a point spaced'downwardly from the 40. from the molten bead but will depend therefrom upper end thereof. This has been accomplished to form'thel/ shown. As a portion of the rod spaced downwardly from the upper end thereof I is moved into engagement with the filament, this portion-of the rod will be thefirst to melt, which causes the upper portion of the rod "to fall over into contact with the filament and form as it v softens a hook somewhat like', the hook 21 formed" on the rod 28. This portion'of the rod m'elts to form the head of molten metal which clings to the filament andf 'holds the remainder oi the rod as in the earlier described form of the invention.

The carrier can be moved backjto' the positionv shown in Fig.1 after the. rod has been vaporized to the extent that the lower end thereof is clear 01' the plate 29. When the first rod is completely vaporized, the carrier can be again moved to bring the next rod into contact 1 with the filament 2| and this process can be continued until ,the entire stock of rods held by the carrier has been completely vaporized.

It is possibl ith the apparatus of thepresen't: I invention, to conveniently form'films of different 1 materials without dismantling the bell jar. This is accomplished by the apparatus of the present invention by forming the rods 28v of different materials so that successive films of different ma-* terials will be formed as the rods are successively evaporated. It'will also be apparent that different materials could be simultaneously evaporated by slight modification of the apparatus.

In/a modified form'of the present invention,

the film-forming material is made up into the held above the base plate III by a vertically extending rod 42 having the lower end thereof fixed in the base plate. As in the earlier de-- scribed form of the present invention, the one end of the chain 40 is held in contact with the filament 2| until the material is melted and the bead 43 is formed. The molten bead holds the end of the chain in heat-receiving contact and as the material of the bead vapori'zes, thematerial of the adjacent link of the chain melts and replenishes the bead.

As the chain is partially supported'by the platform 4!, a larger mass of material can be evaporated than in the method where the material is formed into rods. laminated films can be deposited in this form of the invention by forming the links of the chain of diflerent materials.

It should be understood that, while the present preferred embodiments of the invention have been illustrated and described herein, the inven tion need not be limited thereby but is susceptible oi changes in form and detail within the scope of the appended claims.

We claim:

1. In an apparatus of the type described. an

a I 6 on the surface of a body, an evacuable container; means for evacuating said container; means within said container for supporting the body to receive the film; a heating filament; means for connecting said heating filament to a source oi 7 current; a rack; means for rotata'bly mounting said rack adjacent said filament; means on said rack for mounting a plurality of rods of filmbe seriateLv moved into contact with said filament.

2. 'In an apparatus for forming a film on a body comprising an evacuated container; means for evacuating said container; means within said container for supporting the bod to receive the film; a heating filament; means for connecting said filament to a source of current; a rotatably mounted carrier member; means on said carrier member for holding a plurality of rods of vaporforming material concentric was the axis 0! rotation of said, rack; and means for rotating said rack whereby said rodscan be. seriately moved into contact with said filament.

'4. Inan apparatus for forming a film on the surface of a body, an evacuable container; means for holding the body in the container; means for evacuating said container; a carrier member; means for rotatably mounting said carriertmemberymeans on said carrier member for vertically supporting a plurality of rods of film-forming material so that the same are equally spaced from the axis of rotation of said carrier member; a heated filament; and means for rotating said carrier member, said heated filament being so mounted relative to the axis of rotation of said carrier member that the same lies in the circular path of thevupper ends of said rods as said carrier member is rotated whereby the upper ends of the said rods can be seriately moved into contact with said filament.

5. man apparatus for forming a film on the a surface of a body, an evacuable container; means for evacuating said container; means for supporting the body within said container; a heated filament; means for mounting a plurality of verately moved into contact with said filament by moving said supporting means about said axis; and means for movingvsaid supporting means I about said axis,

JOE E. SWOPE, JR. ARTHUR 1". TURNER.

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