US3224851A

US3224851A - Method of forming a fused energy-conducting device

Info

Publication number: US3224851A
Application number: US173318A
Authority: US
Inventors: Jr John Wilbur Hicks
Original assignee: American Optical Corp
Current assignee: American Optical Corp; Warner Lambert Technologies Inc
Priority date: 1962-01-24
Filing date: 1962-01-24
Publication date: 1965-12-21
Anticipated expiration: 1982-12-21
Also published as: BE693180A

Description

Dec. 21, 1 J. w. HICKS, JR

METHOD OF FORMING A FUSED ENERGY- CONDUCTING DEVICE Filed Jan. 24, 1962 2. Sheets-Sheet 1 INVENTOE JOHN w. HICKS, 1/2.

ATTORNEY wi l 5% [172' Ill- Dec. 21, 1965 J. w. HICKS, JR 3,224,851

METHOD OF FORMING A FUSED ENERGY-CONDUCTING DEVICE Filed Jan. 24, 1962 2 Sheets-Sheet 2 7 4K ATTORNEY United States Patent 3,224,851 METHOD 0F FORMING A FUSED ENERGY- (JQNDUCTING DEVICE John Wilbur Hicks, Jr., Fiskdale, Mass, assignor to American @ptical Company, Southlbridge, Mass, a voluntary association of Massachusetts Filed Jan. 24, 1962, Ser. No. 173,318 11 Claims. (Cl. 65-4) This invention relates to energy-conducting components of the type embodying a plurality of interfused fiber-like elements and has particular reference to novel means and method of making the same.

In fusing bundles of relatively long, thin and generally very flexible fiber elements, ditficulty has been experienced heretofore in achieving a secure, uniform and clean interfacial joinder between each and every one of the respective fibers of the bundle. Interfacial imperfections resulting from separations between individual fibers or particulate matter and/or entrapped gases between the fibers tend to render the bundle or certain sections thereof pervious and not suitable for use when the particular bundle or sections thereof are to be subsequently used as vacuum-tight energy transmitting closures or face plates for devices such as cathode ray tubes or the like. Furthermore, and very importantly, the entrapment of particulate or organic matter and the formation of air or gas bubbles in fused fiber bundles tends to distort the fibers and more particularly the outer layers or claddings thereof by producing thicker and thinner areas or other such imperfections in the claddings at various locations along the lengths of the fibers.

Fibers having claddings along their sides must, for optimum performance, retain their core to cladding thickness ratios substantially uniformly throughout their length especially when bundled together in fused side-byside relation. Thin spots in fiber claddings permit light to stray therethrough from one fiber to another and impair the initial individual light-conducting capabilities of the clad fibers themselves and bundles formed thereof.

In view of the fact that it is often necessary to bundle and fuse fibers of substantial lengths which may be individually as small as only a few microns in diameter and in lots of many thousands or more, it can be appreciated that the initial assembling or bundling cannot avoid interstices between the fibers but can only position the fibers in such an arranged relation as to simulate the desired cross-sectional configuration of the finally fused bundle. In fusing such bundles, these interstices ordinarily provide pockets or traps for gases or other foreign matters particularly when they are deep Within the bundle and, heretofore, it has been extremely difiicult and a troublesome problem to completely outgas these pockets and remove all foreign matter from the fibers during conventional fusing operations.

The present invention deals with the fusing of bundles of relatively long and thin fiber elements and provides a practical solution to the above-mentioned problems of achieving the utmost in secure, uniform and cleanly fused joinders between each and every one of the respective adjoining fibers of a bundle thereof.

Accordingly, a principal object of the present invention is to provide novel means and method for forming an improved fused assembly of a plurality of relatively thin and long fiber energy conducting elements.

Another object is to provide novel means and method for removing and eliminating gases, residues and/ or other foreign matters from between the fiber-like elements of such assemblies and for bringing about secure and uninterrupted fusion completely about the respective adjoining sides of said elements substantially throughout the entire length of said assemblies.

Another object is to provide means and method for accomplishing the above in a relatively simple, etficient and economical manner which offers an assurance of success in duplication.

Another object is to provide a process for fusing a bundle of fibers and novel means for carrying out the process wherein various preparatory steps to fusion and the actual fusion of the fibers are performed systematical- 1y, efiiciently and conveniently with a minimum of expenditure in time and equipment and without handling or in any way subjecting the fiber bundle to contamination during the process.

Another object is to provide apparatus for receiving and supporting assemblies of fiber elements in an enclosure wherein novel means is provided for applying forces to said fiber assemblies when supported therein in such manner as to compress and tighten the same uniformly throughout their lengths during fusion thereof.

Another object is to provide, in apparatus of the above character, means giving access through said enclosure and to said fiber assembly for injecting gases thereinto and/ or for evacuating these and other gases from between the fibers of said assembly in accordance with the requirements of various steps in the process of the invention.

Another object is to provide a process wherein a plurality of grouped fiber elements is placed in a tubular supporting member of heat-softenable material, rinsed with a cleansing solvent, placed within an enclosure of the above-mentioned character, heated and simultaneously vacuumized to remove said solvent, further heated to higher temperatures and flooded with oxygen to burn olf organic residues on the fibers, heated to still higher temperatures above proper fusing temperatures for the fiber materials so as to completely outgas all surfaces thereof, cooled to proper fusing temperatures, flushed with an inert gas and thereafter uniformly forced under pressure applied externally to said tubular member into tightly fused relation with each other simultaneously with the pulling of a vacuum within said tubular member.

A further object is to provide, by the practice of the above procedure, an elongated secure and cleanly fused vaccum-tight fiber energy conducting component which, throughout all cross-sections thereof has substantially identical physical and geometrical characteristics.

A still further object is to provide a structure of the above character from which a plurality of generally wafer-like transverse sections may be cut for use individually or subsequently joined edgewise in side-by-side relation to form large area energy-conducting components.

Other objects and advantages of the invention will become apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary perspective view of a fiber element which is typical of the type used in the fabrication of energy-conducting components in accordance with this invention;

FIG. 2 is a partially broken away perspective view of an assembly of such fiber elements in supporting means therefore;

FIG 3 is an enlarged transverse cross-sectional view of said assembly taken approximately at the location of line 3-3 in FIG. 2;

FIGS. 4 and 5 are diagrammatic longitudinal cross sectional views of apparatus which i illustrative of the type used to carry out the process of the invention;

FIGS. 6, 7 and 8 are fragmentary diagrammatic views of portions of the apparatus shown in FIG. 4 illustrating the function of these portions in carrying out certain steps in the method of the invention;

FIG. 9 is an enlarged cross-sectional view taken approximately on line 99 in FIG.

FIG. 10 is a perspective illustration of the end product of the invention showing a section thereof cut away; and

FIG. 11 is an elevational view of a plurality of these cut-away sections which have been modified and assembled to form a relatively large area energy-conducting component.

Referring more particularly to the drawings wherein like characters of reference designate like parts throughout the various views, it will be seen that the invention relates to the fabrication of a fused bundle of elongated relatively thin fiber-like energy-conducting elements which are contained within a tubular member of heat-softenable material. The end product of the invention is shown in FIGS. 5, 9 and 10 and a fiber element 10 of the type used to form the same is illustrated in FIG. it while an initial assembly of a plurality of such fiber elements in the heatsoftenable tubular member 12 is shown in FIG. 2.

Since, in the end product of the invention, the fiber elements 10 must retain their identity as individual energyconducting channels even though they are fused together in side-by-side relation as an integral unit, they (the fibers 10) each embody an energy-conducting core 14 surrounded by an integral relatively thin cladding 16 which serves as energy-insulating means between the respective core parts when the fibers are bundled together.

The fibers 10 may embody metallic core parts 14 with glass claddings 16 in the event that an electrical energyconducting component is to be made by the process of this invention. However, when making light-conducting components, the core 14 and cladding 16 parts of the fibers 10 would both be formed of glasses having different preselected indices of refraction and/or light-transmitting characteristics.

For purposes of illustration, the following description will relate more particularly to the fabrication of fused light-conducting components wherein all glass fibers 10 are used. However, it should be understood that the invention is equally as applicable to the fabrication of electrical energy-conducting components wherein fibers elements having metallic core parts and glass claddings are used.

A typical light-conducting fiber It would embody a core 14 formed of optical fiint glass or the like having an index of refraction of approximately 1.75 with a relatively thin cladding of crown type or soda lime glass having an index of refraction of approximately 1.52. A cladding to core thickness ratio of approximately 1 to 10 respectively is generally suitable for most purposes of providing an adequate light insulating effect in a bundle of optical fibers of the above character. This ratio, however, may be deviated from to provide thicker or thinner claddings in accordance with the particular types and indices of glasses used in the construction of optical fibers. It is pointed out that the fiber elements 10 might also be provided with core parts 14- formed of special glasses characterized to be primarily transmissive to selected regions of the spectrum and the claddings may be formed of glasses having controlled light-absorbing or other special characteristics. In all cases, the claddings and core glasses must have compatible melting temperatures and coefiicients of expansion.

The fibers 10 may, for example, be formed by techniques such as are set forth in patents numbered 2,980,957 or 2,992,517 or by any suitable method and they may be of the usual monofilament type (each having a single core and sorrounding cladding) or the so-called multifiber type wherein each fiber element, in itself, embodies a plurality of integral lightconducting core sections insulated from one another by individual claddings. Multifibers are formed by drawing a bundle of clad monofilaments, as a unit, down to a fiber size. A method of making this latter type of fiber is shown, for example, in patent number 2,992,516.

In forming the fiber and tube assembly 18, which is illustrated in FIGS. 2, 3 and 4, the fibers 16 which are placed in the tubular member 12 are selected to have such a cross-sectional size as to provide the ultimately fused bundle thereof with a desired image resolving power. That is, image light or orther image forming energy when conducted through a bundle of fibers of the above character is transferred from the receiving to the emitting end thereof as individual image elements, the composite of which makes up the total image. Each image element, as received by a particular fiber, is isolated from adjacent fibers and is of a size approximately equal to that of the cross-sectional area of the particular fiber. Thus, the smaller fibers divide the transferred composite image into smaller or finer components and provide the bundle with higher or better image-resolving powers while larger fibers produce bundles having lower or poorer image resolving powers. For optical purposes, however, the fibers should not be as small in diameter as to approach the wavelength of the particular light which is to be transferred therethrough.

For most purposes, the fibers 10 would be no smaller than a few microns in diameter, for example 3 or 4 mi crons, or they may be as large or larger than 3 or 4 mils in diameter.

In forming the assembly 18, a number of fibers 10 which have been selected for size in accordance with the imageresolving power desired of the component to be formed therefrom are hand-packed or otherwise placed longitudinally in side-by-side relation with each other in the tubular member 12. The fibers 10 are precut to substantially equal lengths somewhat shorter than the tubular member 12 and are bundled together in said tubular member as uniformly parallel as possible in approximately flush end-to-end relation with each other.

The tubular member 12 which may be circular as shown, hexagonal, square or of any desired cross-sectional configuration is preferably formed of crown or soda lime glass or may be formed of any other glass which has a melting temperature and coetficient of expansion approximately equal to or compatible with that of the cladding glasses of the fibers 10. The coethcicnt of expansion of the tubular member 12 may be slightly lower than that of the fiber claddings but, by preference, would not be appreciably higher and its wall thickness, by preference, would be as thin as possible without being too fragile to handle in forming the initial assembly 18 (FIG. 2). A wall thickness of from A of an inch to /8 of an inch would be suitable for most purposes particularly when forming assemblies 18 of from /2 to 2 inches in diameter. It should be understood that tubes 12 having thicker or thinner wall dimensions than those given by Way of example may be used.

In loading the tubular member 12 with the fibers 10, all precautions regarding cleanliness are taken to prevent the occurrence of excessive foreign matter in the assembly of fibers or between the fibers and the inner wall of the tubular member 12 and the fibers It are arranged approximately centrally within the tubular member 12 so as to provide the open or

unfilled areas

20 and 22 internally of the tube adjacent its opposite ends.

The assembly 18 is next flushed or rinsed thoroughly with a high purity solvent such as ethyl alcohol. This can be accomplished by repeatedly dipping or soaking the assembly in the solvent wherein it will find its way through the interstices between the fibers or, alternatively, the solvent may be forced under pressure through the assembly 18 from one end to the other thereof. In this latter instance, the resultant flushing action would enhance the cleansing effect.

Subsequent to the above cleansing operation, if all variations of the process of the invention are to be practiced with greatest facility, means should be provided for selectively passing different gases longitudinally through the assembly 18 and for evacuating these and other gases from the assembly prior to and/or along with a final step of applying a lateral compressing force to the sides of the assembly. This, then, requires that the opposite ends of the tubular member 12 be closed off and provided with means in communication with the inner area of the tubular member through which evacuation and/or flooding of said area with certain gases may be accomplished. Furthermore, the opposite ends of said tubular member 12 must be sealed or otherwise protected from the compressing forces which are to squeeze the assembly 12 laterally substantially without longitudinal compression thereof. I

To accomplish this end, a housing 24 such as is shown diagrammatically in the drawings is provided for receiving and supporting the assembly 18. It should be understood, however, that the housing 24 is merely an exemplification of the type of equipment needed to carry out the process of the invention and it will become apparent hereinafter that extensive modification of the housing 24 and other equipment shown as being associated therewith may be made within the scope of this invention.

The housing 24 is preferably formed of stainless steel or of a similarly characterized material which is of such a wall thickness and so characterized as to be substantially non-corrosive and both physically and geometrically stable when subjected to temperatures as high as several hundred degrees above normal glass fusing temperatures of between 1000 F. and 1600 F. even when subjected to pressures of from 1000 to 2000 or more pounds per square inch. Referring more particularly to FIGS. 4 and 5, it will be seen that the housing 24 comprises a relatively thick walled tubular main body part 26 of a length such that the assembly 18 may be supported therein and a pair of relatively thick end covers 28 and 30 which are removably secured to the respective opposite ends of the body part 26 by means of bolts or the like 32. The body part 26 and covers 28 and 36 may be circular in transverse cross-section or square, hexagonal or of any desired shape provided the respective covers and body part are complementary in shape so as to form a completely enclosed chamber 36. Since the chamber 36 of the housing 24 is intended to be pressurized as will be described in detail hereinafter, a fluid pressure line 38 leading into an opening 46 through the side wall of the body part 26 is provided and

gaskets

42 and 44 are placed between the adjoinment of the body part 26 and the end covers 23 and 39 to form pressure tight seals.

The end covers 28 and 36 are provided with pro tuberances 46 and 48 respectively which, in the assembly of the housing 24, are substantially coaxial with the main body part 26 and extend toward each other into the chamber 36. The protuberances 46 and 4% are shaped to be peripherally complementary to the particular crosssectional shape of the inner walls of the tubular member 12 which is intended to be supported thereby and they are either formed to such a peripheral size as to fit snugly within the

open areas

20 and 22 of the assembly 18 or they may be of a controlled smaller size as shown in the drawings and provided with encircling gaskets 5t and 52 which produce a snug fitting relationship with the tubular member 12 of the assembly 118. It is pointed out that all of the

gaskets

42, 44, 50' and 52 must be formed of asbestos material or some such similarly characterized material which is capable of withstanding temperatures such as mentioned hereinabove.

The

protuberances

46 and 48 are further controlled to be of such a length as to extend a substantial distance into the

open areas

20 and 22 of the assembly 18 preferably without engaging the fibers when the closure of the chamber 36 is made with the assembly 18 therein as shown in FIG. 4.

In order to provide means for flooding the interior of the assembly 18 with gases and/ or evacuating gases from said interior for reasons which will be set forth hereinafter in a detailed description of the process of the invention, passageways 54 and 56 are provided through the respective covers 28 and 3t) and

pipe lines

58 and 60 are extended from these

passageways

54 and 56 to

selector valves

62 and 64. Leading from the valve 62 is an exhaust line 66 and a vacuum line 68 either of which may be selectively placed in communication with the line 58 by operation of the valve 62 which has an L-shaped passageway 7 0 therethrough as shown. In FIG. 4 the vacuum line 68 is shown as being placed in communication with the pipe line 58 and in FIG. 6, the exhaust line 66 is shown as being placed in communication with the pipe line 58. In a similar manner, the valve 64 is provided with an L-shaped opening 72 therethrough and two gas lines '74 and 76 leading to the valve. With the valve 64 positioned as shown in FIG. 4, the pipe line 60 is completely closed off and with the valve 64 positioned as shown in FIG. 7, the gas line 74 is placed in communication with the pipe line 60. In order to place the gas line 76 in communication with the pipe line 60, the valve 64 is positioned as shown in FIG. 8.

In placing the assembly 13 within the housing 24, one of the housing end covers 28 or 30 is removed and the assembly 1.8 is inserted into the housing 24 endwise over the protuberance of the other end cover. The protuberance on the removed end cover is then entered into the adjacent end of the assembly and the initially detached cover is bolted to the main body part 26. The pipe lines 58 and 66 are removably attached to their respective covers by

fittings

78 and 80 to permit removal of the covers from the body part 26 of the housing. However, one or the other or both of the

pipe lines

58 and 60 might be flexible in nature and of such a length between their respective covers and adjacent valves as to permit ready removal of the covers without disconnection of the pipe lines.

Once the assembly 18 of the fibers 10 and tubular member 12 has been rinsed or flushed with the high purity solvent as described above and placed within the chamber 36 of the housing 24 as shown in FIG. 4, the process of the invention, from then on, comprises placing the entire housing within a suitable conventional oven or furnace 82. The furnace 82 may be boxlike in shape as shown (FIG. 4) with outer walls 84 of insulation, inner walls of refractory material 86 supporting electrical heating coils 38 and strategically located slots 90 through the walls thereof which are arranged to receive the

pipings

38, 53 and 60. The slots 90 allow the housing to be lowered into the furnace 82 as shown in FIG. 4 and a slab-like cover or the like 91 is normally placed over the entire furnace to enclose the housing 24 therein. A suitable conventional heat control device 90a controlled by a conventional thermocouple or the like 96/) is provided to regulate the electrical current applied to the heating coils 88 in accordance with the extent to which the assembly 18 within the housing 24 is to be heated during the various steps of the process of the invention.

The

valves

64 and 62 are next positioned as shown in FIG. 4. In this way, the valve 64 closes off the pipe line 66 and effectively seals the adjacent encl of the assembly 18 while the valve 62 opens the opposite end of the assembly 18 to the vacuum line 68. A suction is applied to the line 68 by means of any suitable conventions suction pump or so-called vacuum pump (not shown) so as to evacuate gases from within the tubuiar member 12 and the interstices between the fibers 10 therein. A suction capable of reducing the pressure inside the tubular member 12 to no more than one half an atmosphere is preferred and with this suction continuously applied, the assembly is heated by operation of the furnace heat control means 99:1 to a temperature of approximately from 250 F. to 350 F. until all of the above mentioned cleansing solvent .is completely volatilized and removed by the vacuum line 68. A period of from approximately 3 to 30 minutes with the assembly 18 within the above 0 7 0 given range of temperatures is generally sufficient for this so as to induce a more positive flushing of the assembly step.

The temperature of the assembly is next raised to between 800 F. and 950 F. for several hours (from 2 to 4 or more hours) while oxygen is simultaneously introduced into and through the interior of the assembly 18 by means of an oxygen supply line 74. In order to provide communication between the interior of the assembly 18 and the oxygen supply line 74, the valve 64 is placed in the position shown in FIG. 7. The introduction of oxygen while the assembly 1% is at the above increased temperature causes all organic residues within the assembly 18 to be burned off. The gases or atmosphere resulting from this burn off, which is promoted by the oxygen, may be drawn from the assembly 18 with the vacuum line 68 when the valve 62 is left in the position shown in FIG. 4 or alternatively, the gases may be allowed to exhaust through line as by adjusting the valve 62 to the position shown in FIG. 6. Oxygen would normally be supplied to the line 74 from a conventional pressurized cylinder or tank. Following this, the oxygen supply line 74 is closed off by placing the valve 64 in the position shown in FIG. 4 and the valve 62. is arranged so as to be in the position also shown in P16. 4 to draw a vacuum in the assembly 18 whereupon the temperature of the assembly is raised to approximately 100 F. over the proper fusing temperature for the particular glasses of the fibers 1t} and tube 12 so as to substantially completely outgas all surfaces within the assembly 18 thereof. A period of from 1 to 2 hours at this temperature is suitable for accomplishing this result.

With the assembly 18 being formed of fibers 10 having cores of optical flint glass of an index of refraction of approximately 1.75 and claddings of crown type glass having an index of approximately 1.52 as set forth in the above-given examples and a tubular member of glass having a melting temperature approximately equal to that of the cladding glass of the fibers, a proper fusing temperature would be approximately 1000 F. when the as sembly 18 is compressed under forces of from 1000 to 1500 pounds per square inch in a manner to be described in detail hereinafter. Therefore, for the above outgasing step, a temperature of approximately 1100 F. would be used for the particular glasses given by way of example. With assemblies of fibers having core glasses of lower index of refraction such as a barium flint glass having an index of approximately 1.66, higher fusing temperatures are required and consequently higher outgasing temperatures. Fibers with crown glass claddings and barium fiint glass cores having an index of approximately 1.66 will fuse under pressures such as mentioned above at temperatures of around 1050" F. or 1100 F. and should be outgased at temperatures of approximately ll50 F. or 1200 F.

The above given temperatures are selected only as examples and as it is well known in the art, fiber fusing temperatures may range from below l0OO F. to above 1600 F. and while proper fusing temperatures are related to the characteristics of the particular glasses to be fused, they are also determined in accordance with the pressures applied to the glasses. In general, fusion of heatsoftened glass parts can be accomplished at lower tem peratures when pressure is applied to force said glass parts together while the same glass parts require higher temperatures for fusion without pressure.

Following the step of outgasing the assembly 18, it is reduced to its proper fusing temperature, examples of which are given above, and flushed with an inert gas such as helium to substantially completely displace and thus remove residual gases and/or other extraneous matter from its interior. This is accomplished by adjusting the valve 64 to the position illustrated in FIG. 8 wherein communication between the line 76 (a helium supply line) and the pipe line 60 is made. At this time, pipe line 58 may be retained in communication with the vacuum line 68 with helium by the suction produced within the line (it; or, with the helium being forced through the line 76, under sufiicient pressure to flush through the assembly 18, the helium may be exhausted through the line 66 by adjusting the valve 62 to the position shown in FiG. 6.

After having completely flushed the assembly :8 with helium, the valve 64 is positioned as shown .in FIG. 4 to close off the pipe line 60 and thereby again effectively seal the adjacent end of the assembly 18. The valve 6?. is adjusted as shown in FIG. 4 to place the vacuum line in communication with the pipe line 53 and the best possible vacuum is drawn within the assembly l8. At this time, with the assembly 13 at its proper fusing temperature, examples of which were given above, fluid pressure is applied to the outer walls of the assembly by means of the pressure line 38. This pressure is produced preferably by forcing compressed air into the chamber 35 through the line 33. While it is conceivable that bydraulic fluid might be used in place of compressed air, it (the hydraulic fluid) would have to be heated to approximately the fusing temperature of the assembly if. This would require that the hydraulic fluid be preheated before entering the chamber 36 or that it be placed in the chamber 36 during the entire above-outlined procedure but not under pressure until the time of this last mentioned operation of compressing the bundle 125.

A pressure of from approximately 1000 to I500 pounds per square inch or more is applied to the assembly 18 which, being at its glass fusing temperature, is compressed laterally substantially uniformly throughout its length in the manner illustrated in FIG. 5. The resultant cornpression forces the tubular member 12 against the fibers It) thereby compressing said fibers so as to close all existing interstices internally of the assembly thereof and produce a secure, clean, uniform and vacuum tight fused joinder throughout all cross sections of the initiall separate elements of the assembly. The vacuum system being in operation during the course of the fusing operation assists in compressing the assembly 18 and, at the same time, continuously exhausts excesses of helium from the interior of the assembly 18. Any residual or entrapped helium within the assembly 18 at the time of complete fusion is absorbed into the glasses thereof. it is pointed out that the presence of helium between the parts of the assembly does not inhibit fusion of said parts.

It is also pointed out that regardless of the initial crosssectional shape of the fibers It) or the extent or size of interstices initially existing therebetween, the said fibers 10 will utimately, by the practice of the above-outlined process, assume completely sealed interfitting shapes and be cleanly fused throughout all cross sections substantially as illustrated in FIG. 9.

The resultant fused assembly or component 18 (FIGS. 9 and 10), as it will be referred to hereinafter, is next annealed by slowly lowering its temperature while in the housing 24 over a period preferably lasting several hours or from 1 to 3 or 4 hours. Upon reaching a temperature wherein the housing 24 and assembly 13 can be handled, it is removed from the housing 24.

It should be understood that while certain temperature ranges have been given for the softening and fusing of the glasses recited herein, other glasses might be used and in such instances they might require higher or lower temperatures in accordance with the known characteristics of such glasses. Technical information is available which gives the temperatures of softening, melting and annealing of commercial glasses, all of which may be used in the present invention. Therefore, the various specific temperatures for all glasses adapted for use in the process of this invention are not set forth herein.

Upon removal from the housing 24, the resultant fused assembly 18 may be modified in accordance with its intended use. By way of example, and as shown in FZG. 10, the assembly 18 may be cut transversely into many Wafer-like sections 96. The sections 96 may be used individually as energy-transmitting means (i.e. small face plates for cathode ray tubes or the like) or they may be assembled together to form face plates or the like having relatively large surface areas. That is, the sections 96 may, for example, be each edge ground to a hexagonal shape such as illustrated by the dash outline 98 and assembled together as shown in FIG. 11 whereupon, with heat and pressure, they might be edge fused as a composite integral unit 100 of desired size.

From the foregoing, it can be seen that simple and efiicient means and method have been provided for accomplishing all of the objects and advantages of the invention. Nevertheless, as pointed out hereinabove, many changes in the details of construction, arrangement of parts or steps in the method may be made without departing from the spirit of the invention as expressed in the accompanying claims and the invention is not to be limited to the exact matters shown and described as only preferred matters have been given by way of illustration.

Having described my invention, I claim:

It. The method of forming a fused energy-conducting component of the character described from an assembly of a plurality of energy-conducting fibers each surrounded by a cladding of heat softenable material and contained Within a tubular member of heat softenable material comprising the steps of rinsing said assembly with a high purity cleansing liquid, removing residues of said liquid from said assembly, introducing a gas which will promote oxidation of organic matter into said tubular member, subjecting said assembly of fibers to heat of a temperature sufificient to oxidize existing organic residue within said tubular member and to outgas component parts of said assembly which are disposed internally of said tubular member, flushing said assembly with an inert gas to displace residual gases therein and fusing together component parts of said assembly by applying heat of fusing temperature thereto while compressing said fibers into tight interfitting relation with each other by the application of external pressure upon said tubular member.

2. The method of forming a fused energy-conducting component of the character described from a plurality of glass clad energy-conducting fibers comprising placing said fibers in a heat-softenable tubular member, passing a cleansing solvent through the resultant assembly of said fibers and tubular member, heating said assembly to controlled successively varying temperatures sufficient to respectively volatilize residues of said solvent in said assembly and substantially completely oxidize oragnic residues therein and dispel adsorbed and absorbed moisture and gases from internally disposed parts of said assembly, flushing said assembly with an inert gas to displace and expel residual gases therein, bringing said assembly to a proper temperature for fusing its parts together and applying fluid pressure externally upon said tubular member of said assembly While simultaneously creating a vacuum internally thereof to compress said tubular member against the fibers therein and to thereby urge said fibers into tight interfitting fused relation with each other.

3. The method of forming a fused energy-conducting component of the character described from an assembly of a plurality of glass clad energy-conducting fibers contained within a heat-softenable tubular member comprising rinsing said assembly internally with a high purity cleansing solvent, drawing a vacuum within said assembly while simultaneously heating the same to a temperature of approximately from 250 F. to 350 F. for a time period sufficient to substantially completely volatilize residue of said solvent, increasing the temperature of said assembly to approximately from 850 F. to 900 F. and holding the same at said increased temperature for from approximately 2 to 6 hours while simultaneously introducing oxygen thereinto to oxidize organic matter therein, further increasing the temperature of said assembly to approximately above a normal temperature required to fuse together the respective component parts thereof and retaining said assembly at said temperature for a period of from approximately /2 to 2 hours so as to substantially completely dispel adsorbed and aborbed moisture and gases from said parts thereof, reducing the temperature of said assembly to approximately a minimum fusing temperature suitable for the particular glasses of said fiber claddings, flushing said assembly internally with helium to displace residual gases, producing a relatively high vacuum internally of said assembly, applying an ambient compressing force of from approximately 1000 to 1500 pounds per square inch against the major portion of the outer surface area of said assembly to compact and fuse said fibers together and annealing the resultant assembly.

4. The method of forming a fused energy-conducting component of the character described from a plurality of glass clad energy-conducting fibers comprising the steps of placing said fibers in side-by-side relationship within a heat softenable tubular member, rinsing the resultant assembly of said tubular member and fibers with a high purity cleansing solvent, drawing a vacuum within said assembly and heating the same to a temperature substantially only sufficient to volatilize residues of said solvent, increasing the temperature of said assembly sulficiently to oxidize existing organic residues therein and simultaneously introducing a gas into said assembly to promote oxidation of said residues, further increasing the temperature of said assembly to a point suflicient to outgas the surfaces of component parts of said assembly, adjusting the temperature of said assembly to approximately the minimum required to effect fusion of said fibers one to the other, flushing the assembly with an inert gas to expel and displace residual gases therein and applying external pressure to said tubular member while simultaneously drawing a vacuum internally thereof to force said tubular member against the fibers therein to urge said fibers into tight interfitting fused relation with each other.

5. The method of forming a fused energy-conductive component of the character described from an assembly of a plurality of glass clad energy-conducting fibers contained within a heat-softenable tubular member having open ends comprising the steps of rinsing the assembly of said tube and fibers with a high purity cleansing solvent, placing said assembly within a chamber adapted to be pressurized and with said open ends of said tubular member sealed from communication with said chamber, access to the interior of said tubular member being provided through said open ends thereof, placing said compression chamber within heating means, producing a vacuum within said assembly, heating said assembly to a temperature sufficient to volatilize residues of said cleansing solvent therein, raising the temperautre of said assembly to a temperature sufiicient to oxidize organic residues existing within said assembly and simultaneously introducing oxygen into said assembly to promote oxidization of said organic residues, increasing the temperature of said assembly to a point above that normally required for fusing the parts thereof to outgas surfaces of components of said assembly disposed internally of said tubular member, reducing the temperature of said assembly to said normal fusing temperature and holding said assembly approximately at said fusing temperature for a period of time sufficient to permit flushing of the interior thereof, flushing the interior of said assembly with an inert gas to displace and expel existing residual gases therein, producing a relatively high fluid pressure Within said chamber along with a vacuum internally of said assembly to force said tubular member of said assembly laterally against the fibers therein so as to compress said fibers into tightly fused interfitting relation with each other.

6. The method of forming a fused energy-conducting component of the character described from an assembly of a plurality of glass clad energy-conducting fibers contained within a heat-softenable tubular member and which has been rinsed with a high purity cleansing solvent comprising the steps of heating said assembly to controlled successively varying temperatures which are adapted to respectively oxidize organic matter therein and dispel adsorbed and absorbed gases from the various parts of said assembly, flooding the interior of said assembly with an inert gas to displace residual gases therein, bringing said assembly to a fusing temperature and producing a vacuum internally of said assembly together with a compressing force externally thereof to force said tubular member against the fibers therein and cause said fibers, under said fusing temperature, to assume tight interfitting crosssectional shapes and become fused to each other and to said tubular member.

'7. The method of forming a fused energy-conducting device which comprises the steps of placing longitudinal ly within a tube of heat-softenable material a multiplicity of relatively long and thin energy-conducting fibers whose outer side surfaces are formed of heat fusible material, said fibers having undesired interstices therebetween, heat ing the combination of said tube and fibers to a temperature sutficient to soften said tube and fuse together respective side surfaces of said fibers and applying relatively high fluid pressure about the exterior of said tube, said pressure being of an amount sufiicient to force said tube radially inwardly against said fibers to compress said fibers sufficiently to close said interstices and fuse the side surfaces of said fiber together into a unitary assembly.

8. The method of forming a fused energy-conducting device which comprises the steps of placing longitudinally within a tube of heat-softenable material having at least one open end a multiplicity of relatively long and thin energy-conducting fibers whose outer side surfaces are formed of fusible material, said fibers having undesired interstices therebetween, heating the combination of said tube and fibers to a temperature sufificient to soften said tube and fuse together respective side surfaces of said fibers, drawing a vacuum internally of said heat-softened tube to evacuate air and gases therein while simultaneously applying fluid pressure about the exterior of said tube of a force which in conjunction with the pull of said vacuum will compress and force said tube against said fibers to close and seal said interstices and bring about a tight interfitting fused relationship between said fibers.

9. The method of forming a fused energy-conducting device which comprises the steps of placing longitudinally within a tube of heat-softenable and fusible material a bundle of relatively long and thin energy-conducting fibers Whose outer side surfaces are formed of heat fusible material, said fibers having undesired interstices therebetween, heating the combination of said tube and fibers to a temperature sufiicient to soften said tube and fuse together respective side surfaces of said fibers and applying fluid pressure about the exterior of said tube, said fluid pressure being relatively great with respect to that of the internal environment of said tube and of an amount sulficient to compress and force said tube inwardf2 ly against said bundle to compress said fibers sufficiently to close said interstices and fuse the side surfaces of said fibers together into a unitary assembly and thereafter cooling said assembly.

10. The method of forming a fused energy-conducting device which comprises the steps of placing longitudinally within a tube of heat-softenable and fusible material a bundle of relatively long and thin energy-conducting fibers whose outer side surfaces are formed of heat fusible material, said fibers having undesired interstices therebetween, displacing air and residual gases in said interstices with an inert gas, heating the combination of said tube and fibers to a temperature sufiicient to soften said tube and fuse together respective side surfaces of said fibers and applying relatively high lluid pressure about the exterior of said tube, said fiuid pressure being relatively great with respect to that of the internal environment of said tube and of an amount suflicient to compress and force said tube inwardly against said bundle to compress said fibers sutficiently to close said interstices and fuse the side surfaces of said fibers together into a unitary assembly and thereafter cooling said assembly.

11. The method of forming a fused energy-conducting device which comprises the steps of placing longitudinally within a tube of heat-softenable and fusible material a bundle of relatively long and thin energy-conducting fibers whose outer side surfaces are formed of heat fusible material, said fibers having undesired interstices therebetween, displacing air and residual gases therein with an inert gas, drawing a vacuum internally of said tubular member to effect an inwardly directed pulling force upon said tubular member, heating the combination of said tube and fibers to a temperature sufficient to soften said tube and fuse together respective side surfaces of said fibers, applying a relatively high fluid pressure about the exterior of said tube of a force sufficient to act in conjunction with said force of said vacuum to compress and force said tube against said bundle and compress said fibers thereof sufficiently to close said interstices and fuse the side surfaces of said fibers together into a unitary 7 assembly and thereafter cooling said assembly.

References Cited by the Examiner UNITED STATES PATENTS 1,113,260 10/1914 Tardieu 156--38l 1,240,438 9/1917 Grifliths 15681 XR 1,260,384 3/1918 Huebner 156-81 XR 2,213,479 9/1940 Volt et al 15681 2,311,704 2/1943 Simison.

2,363,059 11/1944 Greene et al 156-81 2,484,003 10/1949 Simison 654 XR 2,812,796 11/1957 Mac Henry 156381 2,992,516 7/1961 Norton 156296 XR 2,992,956 7/1961 Bazinet 156-296 XR 3,004,368 10/1961 Hicks 156296 XR 3,119,678 1/1964 Bazinet 156296 XR EARL M. BERGERT, Primary Examiner.

Claims

1. THE METHOD OF FORMING A FUSED ENERGY-CONDUCTING COMPONENT OF THE CHARACTER DESCRIBED FROM AN ASSEMBLY OF A PLURALITY OF ENERGY-CONDUCTING FIBERS EACH SURROUNDED BY A CLADDING OF HEAT SOFTENABLE MATERIAL AND CONTAINED WITHIN A TUBULAR MEMBER OF HEAT SOFTENABLE MATERIAL COMPRISING THE STEPS OF RINSING SAID ASSEMBLY WITH A HIGH PURITY CLEANSING LIQUID, REMOVING RESIDUES OF SAID LIQUID FROM SAID ASSEMBLY, INTRODUCING A GAS WHICH WILL PROMOTE OXIDATION OF ORGANIC MATTER INTO SAID TUBULAR MEMBER, SUBJECTING SAID ASSEMBY OF FIBERS TO HEAT OF A TEMPERATURE SUFFICIENT TO OXIDIZE EXISTING ORGANIC RESIDUE WITHIN SAID TUBULAR MEMBER AND TO OUTGAS COMPONENT PARTS OF SAID ASSEMBLY WHICH ARE DISPOSED INTERNALLY OF SAID TUBULAR MEMBER, FLUSHING SAID ASSEMBLY WITH AN INERT GAS TO DISPLACE RESIDUAL GASES THEREIN AND FUSING TOGETHER COMPONENT PARTS OF SAID ASSEMBLY BY APPLYING HEAT OF FUSING TEMPERATURE THERETO WHILE COMPRESSING SAID FIBERS INTO TIGHT INTERFITTING RELATION WITH EACH OTHER BY THE APPLICATION OF EXTERNAL PRESSURE UPON SAID TUBULAR MEMBER.