US3783821A

US3783821A - Planetary workholders

Info

Publication number: US3783821A
Application number: US00164336A
Authority: US
Inventors: C Dobson; K Willmott
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-03-02
Filing date: 1971-07-20
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08

Abstract

A movable workholder in a vacuum enclosure, for vacuum deposition, including a planetary system comprising a number of planet workholders engaging a horizontal driving annulus at their lower edges and resting on a sun wheel at their upper edges, the planets being held apart by a rotary spider. The angular inclination of the planets can be adjusted by locating them selectively on one of two spaced sun wheels, or by tilting one of the sun wheels so that the planets tilt as they rotate. The apparatus may include means for rotating sections of the planets to expose the opposite sides of the workpieces, and each planet may incorporate a subsidiary planetary system.

Description

United States Patent 1191 Dobson et al.

1111 3,783,821 Jan. 8, 1974 1 PLANETARY WORKHOLDERS W mott, 158 Linden 01., both of Newbridge, England [22] Filed: July 20, 1971 Mar. 2, 1971 Great Britain ..5745/71 lune 14, 1971 Great r9 1: ..217 /71 [52] U.S. Cl. 118/48, 269/57 [51] Int. Cl. C23c 11/08 [58] Field 'of Search ..l

l8 1W

5, 500, 503, 53;

[ 56] References Cited UNITED STATES PATENTS 3,675,624 7/1972 Hunts et a1. 118/503 3,128,205 4/1964 lllsley 118/49 3,523,517 8/1970 Corbani 118/500 3,594,227 7/1971 Oswald l17/107.l X 3,608,519 9/1971 Richardson 118/48 FOREIGN PATENTS OR APPLICATIONS 2,029,020 1/1971 Germany 1 18/49 Primary Examiner-Morris Kaplan Attorney-William D. Hall et a1.

[57] ABSTRACT A movable workholder in a vacuum enclosure, for vacuum deposition, including a planetary system comprising a number of planet workholders engaging a horizontal driving annulus at their lower edges and resting on a sun wheel at their upper edges, the planets being held apart by a rotary spider. The angular inclination of the planets can be adjusted by locating them selectively on one of two spaced sun wheels, or by tilting one of the sun wheels so that the planets tilt as they rotate. The apparatus may include means for rotating sections of the planets to expose the opposite sides of the workpieces, and each planet may incorporate a subsidiary planetary system.

16 Claims, 8 Drawing Figures PATENTEIJ 81974 3.783.821

SHEET u 0F 5 FIG. 5.

PAIEME JAN 8 I974 SHEET 5 OF 5 FIG. 6.

Fla]

PLANETARY WORKHOLDERS This invention relates to apparatus for use in vacuum deposition of the type including means within a vacuum chamber for supporting workpieces and for moving the workpieces during the deposition process in order to control the rate or spread of the deposited coating.

It is known in such vacuum deposition apparatus to provide an inverted bowl-shaped, work-supporting carriage which is rotated slowly about a vertical axis, with the metal evaporating source situated at the centre of the bowl. The slovgrotation of the bowl provides some uniformity in the deposited coating on different sections of the workpieces. This system, however, does not provide optimum results in all applications since the angular relationship or attitude of individual workpieces or portions of a workpiece can differ and may be approximately constant or within a limited range during the whole process. To provide more uniform coating and to assist in coating effectively into small ledges, steps, or crevices in a workpiece it has been proposed to provide a planetary epicyclic work-supporting mechanism in which a complete circular planet work-holder is made to rotate about its axis while it moves bodily about the main vertical axis of the whole structure. As a result an individual small workpiece, which may initially be at the top of the planet, gradually moves to'the bottom before it swings around the planet axis up to the top position again. In this way each individual work- 'piece is moved not only around the main rotary axis but also is raised and lowered and tilted due to the bowl shape of the planet, thus in effect pivoting about a horizontal transverse axis. For very accurate precise coating requirements, however, even this planetary workholder system does not provide a fully satisfactory result and it is an object of the present invention accordingly to provide means for adjusting, controlling, or governing the position and/or attitude of individual workpieces, or portions of a larger workpiece, in such vacuum deposition apparatus, which will more effectively meet some of these demanding requirements.

Broadly from one aspect the invention consists in apparatus for use in vacuum deposition, including a movable work-supporting mechanism including an epicyclic system comprising a planet assembly which itself consists of a subsidiary epicyclic system including a subsidiary planet, which latter includes means for mounting a workpiece.

From another aspect the invention consists in apparatus for use in vacuum deposition including movable work-supporting mechanism, comprising an annulus, a planet assembly, and a sun or planet carrier, and means for driving the annulus, and/or the sun, and/or planet carrier, the planet assembly comprising a subsidiary annulus, a subsidiary planet and a subsidiary sun or planet carrier.

In a compound epicyclic system a difficulty arises in providing a reaction force for the subsidiary planet system and according to a preferred feature of the invention one-component of the subsidiary epicyclic planetary system is prevented from rotation by a gravitational weight.

From another aspect of the invention the problem is solved not by providing a subsidiary planetary system but by arranging that the inclination or attitude of one of the main planet assemblies shall be varied as it moves around the main axis. Thus from this aspect the -rail around the periphery of the supporting plate, and

engaging at its upper end on a smaller guide ring or member, the said guide ring being of non-circular or non-uniform profile or shape such that as the workholder rotates and moves around the periphery of the main supporting plate, its upper edge rises and falls, so changing the attitude of the work-holder.

In many applications it is required that the workpiece or article to be coated should be exposed on two or more sides to the treatment, and it is often necessary after exposure on one side to break the vacuum, open the chamber and insert the workpiece, reclose the chamber and recreate the original vacuum conditions.

- This is laborious, time consuming and also wasteful of energy, and in some cases where the workpiece has to be heated slowly to the selected temperature before the operation can begin (and/or cooled from this temperature), this interruption can add very considerably to the total time of the treatment process.

Accordingly it is another object of the invention to provide an improved vacuum deposition apparatus which will at least partly overcome some of these disadvantages, and which may comprise a workholder or support arranged to be mounted within a vacuum chamber, so as to present one side of a workpiece towards a treatment source such as a source of evaporation, and reversing means for moving the work-hold so as to present the other or another side of the workpiece towards the said source, without disturbing the vacuum conditions in the chamber.

Preferably the workholder is arranged to be movable in a first sense, while presenting the first side towards the said source, and movable also in the same first sense while presenting the other side thereof to the source. For example the work-holder may be mounted for rotary movement about one axis for this said movement in the first sense, and for pivotal movement about another transverse axis for reversing the side thereof presented towards the source.

In any case the reversing means is preferably relatively stationary within the vacuum chamber and is engageable with the work-holder when in a predetermined position of its range of movement in the first sense.

In a particular preferred arrangement the workholder is a generally circular rotary frame or ring, containing one or more panels mounted for pivotal move.- ment within the frame or ring, preferably about radial axes, so as to present opposite sides thereof in the direction of the source. The work-holder may for example be a planetary member arranged to rotate about its own axis while moving simultaneously in an orbit around a main axis.

The invention may be performed in various ways and two specific embodiments will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of one form of vacuum deposition apparatus according to the invention,

FIG. 2 is a somewhat diagrammatic side elevation of part of the apparatus of FIG. 1, on an enlarged scale,

FIG. 3 is a plan view of a modification, comprising a planetary assembly for use in the apparatus of FIG. 1, with a subsidiary planetary system in the main planet,

FIG. 4 is a side elevation partly in section of the subsidiary planetary system of FIG. 3,

FIG. 5 is a side elevation, similar to FIG. 1,.showing another embodiment of the invention, I

FIG. 6 is a plan view, on an enlarged scale, of one of the planet work-holders of FIG. 5,

FIG. 7 is a sectional view through the planet workholder of FIG. 6, and

FIG. 8 is a diagrammatic side elevation, similar to FIG. 2, showing part of yet another modification of the invention.

In all these illustrated examples, the invention is applied to vacuum deposition apparatus of the type comprising a circular base-plate 10 designed to cooperate with a glass dome 11 to form an enclosure in which a high vacuum can be developed by conventional vacuum pumps (not shown) communicating with the interior of the vessel through an aperture 12 in the baseplate. The base-plate also is provided with a number of sealed connections indicated at 13 for services required within the vessel such as high tension and low tension electric supplies, ducts for supply and return of inert gases or other fluids, heating and cooling supplies, and metering, indicating or other electrical circuitry. In addition, there may be provision for rotary or linear mechanical drives 14 to mechanisms within the sealed chamber.

In the first example, the work-supporting-apparatus within the chamber comprises a number of spaced upright pillars 15 attached at their upper ends to a horizontal fixed circular ring 16 which acts as a support for a rotary work-holder carriage. The carriage itself comprises another rotary horizontal ring 17, somewhat smaller in diameter, and having three spaced bearing wheels 18 resting on the fixed ring 16 and engaging the inner lip of the ring 16 to hold the rotary carriage concentric. From this movable ring a series of arms 19 extend upwards to another ring-20 at a higher level which acts as the moving annulus of an epicyclic planetary system and has a groove 21 in its upper edge (see FIG. 2) to act as a guide groove for the individual planets. Each planet is a dish-shaped metal disc 25 formed with a number of circular apertures or windows 26 to support the indivdiual workpieces or substrates whose under surfaces are to be metal coated. Each planet has a bead or ridge 27 around its periphery which engages in the groove 21 of the annulus ring 20 while the upper part of each planet engages or rests on a smaller diameter sun wheel or sun ring 28 positioned on-the central vertical axis and held stationary by vertical studs 29 Secured to a top plate 30 which is in turn secured to and mounted from the fixed ring 16 by three external bent legs 32.

Means are provided for causing the smaller diameter rotary ring 17 to rotate about the vertical axis, and to carry with it the upper annulus 20, which thus causes the three planet discs 25 to move bodily around the vertical central axis and simultaneously rotate about their individual rotary axes which are inclined inwardly and downwardly towards the main central axis as illustrated. The drive means in this example of the invention comprises a small friction'wheel 35 driven through a gear box 36 mounted on the fixed ring 16 and engaging against the lower surface of the moving ring 17, this friction wheel being driven by an external motor (not shown) via the rotary transmission 14 passing through a seal in the base-plate 10. Alternatively a small electric motor may be incorporated within the vacuum enclosure.

The sun wheel or sun ring 28 may be positioned horizontally so that each of the planet discs 25 maintains a uniform inclination as it rolls around the annulus ring 20, but in this embodiment of the invention this upper sun ring is inclined so that its effective surface is lower on one side of the axis than on the other, as clearly seen in FIG. 2. As a result each planet disc 25 tends to rock upwards and downwards between the positions shown on the left and right sides of FIG. 2, as it moves bodily around the main central axis. It follows that each individual substrate in a window 26 not only oscillates or orbits between the lower and upper positions on the planet disc itself, but also cyclically varies in its attitude or angle with respect to the horizontal, as the planet rocks. This is of assistance in providing more uniform coating and also assists in obtaining better coating when the substrate has small ledges or steps.

The planets are held out of direct contact with one another, as they rotate around the vertical centre axis, by a spider assembly including three wire loops 40 which are secured to and depend from a rotary disc 41 positioned above the sun ring 28 and located and guided by a plurality of radial bearing rollers 42 which move between the fixed top plate 30 and another fixed plate 43 spaced below the plate 30. The angular shape of each spider loop 40 is such that the planets tend to be held down against the sun ring 28, and by avoiding direct contact between the rims of adjacent planets any tendency for the planets to ride off the ring 28 is much reduced or eliminated.

The planetary fixturing of the prior art provides for a stationary lower annular member and an upper rotating sun-wheel. Such an arrangement has several dis tinct disadvantages over the apparatus of this invention wherein the lower annular member is driven so as to rotate about a vertical axis while the upper sun-wheel or wheels remain stationary. Thus, with the prior art apparatus, it is frequently necessary to provide a driving means for the driven upper sun-wheel which driving means extends through the path between the workpieces and the sources of heat and sources of deposition material. This creates problems since the combination of heat and vacuum is, at best, a very hostile environment for mechanical elements; thus, the large amount of thermal expansion of the mechanical elements which results from their being placed in such an environment in itself creates severe problems, and it is therefore desirable to avoid having any such mechanical drive means situated in such manner as to result in its becoming any hotter than necessary. This is particularly true of any bearings which are particularly susceptible to maintenance problems where subjected to high temperatures and vacuum atmosphere.

Also the ability to conveniently drive the lower annular member as, for example, by a friction drive means as disclosed herein, means that the rotary drive mechanism can be quite simple and thus require the transmission of only a minimal torque through the rotatable vacuum feed-through means. This also results in simplicity of construction and also of maintenance. The rotary drive means of this invention may then also be readily constructed in such manner as not to interfere in any manner with the inclination of the planetary workholders whose angle of inclination can thus be readily selected at will without regard to any interference with a drive mechanism. Also, the removal of the drive mechanism from the upper part of the vacuum chamber means that it then becomes easier to load the various planetary members with the workpieces which can then be quite readily dropped into place. As a consequence of these several advantages resulting from having the lower annular member rotatable with the upper sun-wheel stationary, there results the ability to operate the apparatus of this invention in temperatures as high as 700 C. as compared with the prior art apparatus which is generally limited to maximum temperatures of about 300 C.

In the modification illustrated in'FIGS. 3 and 4, the main components of the apparatus are identical with that shown in FIGS. 1 and 2, but the individual planet discs 25 are replaced by planet assemblies each of which comprises a subsidiary epicyclic system. Each of these systems includes an annulus ring 45, which corresponds to the bead 27 on one of the planet discs 25, and rests at its lower edge in the groove 21 on the main annulus ring 20, and at its upper edge on the central sunwheel 28, as in the previous example. A pair of arms 46 are secured to this ring and support a spindle 47 in a bearing 48 positioned centrally of the ring, and carrying a sun-wheel or sun ring 50. A number of subsidiary planets in the form of small hoops 51 engage respectively in a groove on the inside of the planet annulus 45 and also rest on the edge of the secondary sun-wheel 50. The sun-wheel 50 is allowed to rotate with respect to the bearing 48 but is prevented from rotation in absolute terms by a weight 52 attached to part of its edge, which holds the sun-wheel in a constant attitude as the planetary assembly moves round the main vertical axis of the equipment. The sub-planet hoops 51 are separated by spacer vanes 53 attached to a rotary plate 54 mounted to rotate on the bearing sleeve 48. I

In operation, the rotation of the main annulus ring causes the individual planet rings or annulae 45' to move bodily around the main vertical axis and also to rotate about their individual axes as they move, this movement producing corresponding bodily and rotational movement of the frameworks 46 attached to the planet rings. The sun-wheels 50 mounted in the individual spider bearings 48 do not rotate however and the individual sub-planet rings or hoops 51 are therefore caused to perform planetary epicyclic movements around and within each planet annulus.

As a result, each individual substrate positioned within one of the subsidiary planet rings 51 is caused to rotate about its own central perpendicular axis and simultaneously to swing bodily around the spider spindle axis of the respective planet, while the planet ring assembly as a whole moves slowly around the main vertical axis of the structure.

FIGS. 5 and 6 illustrate another modification of the invention including a device for turning over the individual workpieces, so as to coat their opposite surfaces, without having to break the vacuum and open up the vacuum enclosure. The work-holder equipment illustrated is basically similar to that illustrated in FIG. 1,

and like parts are illustrated by like reference numerals. In this example, each of the planets 25 is replaced by a circular hoop 61 which locates in the groove 21 of the top ring 20 and also rests on the stationary overhead sun ring 28 which in this example is horizontal.

Means are provided for reversing the individual work supports so that opposite sides of the workpieces can be metal coated without breaking the vacuum. For this purpose, each planetary work-holder comprises a central cup-shaped hub or boss 64 (see FIGS. 6 and 7) having four radially extending arms 69 attached to the surrounding rim 61. In each of the open quandrants is mounted a panel or frame 63 which may be formed with a number of circular apertures or windows to receive individual lenses or other workpieces. Each of these panels is arranged to be capable of pivoting about a radial axis on a pair of aligned pivots 62, the inner pivot being connected in eachcase to a drive gear 65 which engages with a cup or contrite" gear 67 mounted on a stub shaft 68 carried by a central bearing in the hub 64. The gear 67 has a pair of upstanding pins 66 by which it can be driven, and it will be seen that rotation of this gear 67 causes all the individual panels 63 g to rotate about their individual axes so as to reverse their direction of presentation.

The mechanism for driving the reversing gears 67 of the three planets is illustrated in FIG. 5 and comprises an inclined rotary drive shaft having a T-piece 76 at its inner end, designed to connect with the pins 66 when required. The upper end of the shaft 75 is interconnected via a bevel gear pair 77 to a vertical rotary drive shaft 78 supported in abearing 79 at its upper end and in a bearing 80 at its lower end where it passes through the fixed ring 16. The bottom end of this shaft 78 passes through a rotary seal ,in the base plate (not shown) designed to permit the shaft to be rotated and also raised and lowered. The upper bearing support 79 slides on one of the fixed legs 32 and also supports the inclined shaft 75. Thus the whole unit including the

drive shafts

78 and 75 and the bearing shaft 79 can be selectively raised clear of the planetary work-holders or lowered until the T-piece 76 engages in a pair of drive pins 66. In use, the planetary drive system is slowly inched into a position where the hub of one of the planets is aligned with the

flip drive mechanism

75, 76 the actual final position being determined by visual inspection through the glass bell jar or a viewing ap'erture in the chamber wall, and the flip mechanism is then lowered and actuated to cause the panels of that planet to invert. The planets are then again inched sideways by means of the

drive

35, 36 and the process repeated for the next and final planets.

Instead of the contrite spur gear 67, a worm drive gear may be used and this has the main advantage that the gear mechanism is not freely reversible, so that the panels 63 will not shift from their angular positions when the

flip mechanism

75, 76 is disengaged.

In the further modification illustrated in FIG. 8, the apparatus is basically similar to that illustrated in FIGS. 1 and 2, and again like parts are indicated by the same reference numerals. In this example, however, the inclined sun ring 28 of FIG. 2 is replaced by a pair of vertically spaced fixed sun rings 82, 83 of different diameters, and so positioned that the planet discs 25 may be positioned selectively at will either to rest on the upper ring 83, or the lower ring 82, as shown at the left and right sides of FIG. 8. In this way the inclination of each planet work-holder can be selected at the start of each coating operation without the need for complex adjusting devices or procedures.

We claim:

1. Apparatus for use in the vacuum deposition of workpieces comprising,

means defining at least in part a vacuum chamber including a base and a removable upper casing,

a lower annular support member rotatable about an axis perpendicular to its plane,

a second annular support member lying parallel with and spaced vertically above said lower support member,

a plurality of circumferentially spaced upstanding elements rigidly interconnecting said lower annular support member and said second annular support member,

at least one stationary sun-wheel mounted above said support member and defining a peripheral edge,

mounting means for said sun-wheel, connected to said base,

at least one freely-supported removable disc-shaped work-holder,

support means for said workholder for supporting said workpiece for rolling movement along said second support member solely by an upper face of said second annular member and by said peripheral edge of said upper sun-wheel,

means for rotating said lower annular support member which means is disposed entirely below said lower annular member, and includes a driving element engaging the said lower annular member,

power supply means passing through said base,

and means for supporting said lower support member including a plurality of spaced bearings disposed below said lower annular member, said supporting means being operatively connected to said base,

the lower lip of said casing lying below said lower support member,

whereby the only elements above said lower annular support member which are movingly engaging comprise said workholders which roll along said second annular member and along said sun-wheel, and whereby said workholder and said two support members are accessible on removal of said casing from said base.

2. The apparatus of claim 1 which further includes workpiece reversing means including actuating means external of said vacuum chamber and means extending inwardly of said vacuum chamber to said workpiece support means for permitting reversal of at least one of said workpieces while maintaining the vacuum in said chamber.

3. The apparatus of claim 2 which includes means for moving said support means in a first sense while said workpiece is supported in a first position by said workpiece reversing means and moving said workpiece also in the same first sense while said workpiece is held in its reverse position by said workpiece supporting means.

4. The apparatus of claim 3 including means for mounting said workpiece supporting means to permit rotary movement about one axis for said movement in the first sense and permitting also pivotal movement of said workholder about another transverse axis in response to said reversing means.

5. The apparatus of claim 4 comprising a single reversing means for selectively reversing a plurality of said workholders, said single reversing means being engagable with a particular one of said workholders when such particular workholder has moved in said first sense to a predetermined position.

6. The apparatus of claim 1 wherein each said workholder comprises a generally circular rotary frame having at least one panel mounted for pivotal movement within said frame.

7. The apparatus of claim 6 wherein each said workholder is a planetary member.

.8. The apparatus of claim 1 wherein the peripheral edge of said stationary sun-wheel is noncircular relative to the axis of rotation of said second annular support member so that as said workholder rotates and moves around the periphery of said annular upper face of said second annular member the upper edge of said workholder rises and falls thereby changing the attitude of said workholder.

9. The apparatus of claim 1 wherein said stationary sun-wheel is circular and lies in a plane parallel to that of said second annular support member.

10. The apparatus of claim 8 wherein said stationary sun-wheel lies in a plane forming an angle with the plane of said second annular support member.

11. The apparatus of claim 1 wherein said driving element comprises a drive wheel engaging the lower surface of said lower annular support member.

12. The apparatus of claim 1 wherein said workholder comprises a subsidiary planet forming a subsidiary epicyclic system, said subsidiary planet including means for mounting a workpiece.

13. The apparatus of claim 12 wherein said workholder comprises an annulus and said subsidiary planet is rotatable relative to said annulus, means including both said annulus and said subsidiary planet for supporting a plurality of workpieces, and means for preventing absolute rotation of said rotatable member' as said annulus rotates.

14. The apparatus of claim 1 which comprises two stationary sun-wheels one above the other and so positioned that the upper edge of said workholder may be inclined selectively against the peripheral edge associated with either of said stationary sun-wheels, each of said stationary sun-wheels providing thereby a different angle of inclination of the workpiece as the workpiece one rotary spider having arms which extend between said workholders to avoid direct contact therebetween, each of said spiders being freely rotatable about the axis of rotation of said lower annular support member. 16. Apparatus for use in the vacuum deposition of workpieces comprising:

means for defining at least in part a vaccum chamber, a lower annular support member rotatable about an axis perpendicular to its plane, at least two sun-wheels supported at varying distances above said lower annular support member and each defining a peripheral edge, at least one disc-shaped workholder, support means for said workholder including means for supporting an edge of said workholder and further including the peripheral edge of a selected one of said sunwheels also supporting the edge of said workholder relative to the axis of rotation of said lower holder, support member being dependent upon which of and means forrevolving said workholders in planesun-wheels is in engagement with the edge of said tary fashion about said annular support member I workholder.

with the angle of inclination of each said work-

Claims

1. Apparatus for use in the vacuum deposition of workpieces comprising, means defining at least in part a vacuum chamber including a base and a removable upper casing, a lower annular support member rotatable about an axis perpendicular to its plane, a second annular support member lying parallel with and spaced vertically above said lower support member, a plurality of circumferentially spaced upstanding elements rigidly interconnecting said lower annular support member and said second annular support member, at least one stationary sun-wheel mounted above said support member and defining a peripheral edge, mounting means for said sun-wheel, connected to said base, at least one freely-supported removable disc-shaped work-holder, support means for said workholder for supporting said workpiece for rolling movement along said second support member solely by an upper face of said second annular member and by said peripheral edge of said upper sun-wheel, means for rotating said lower annular support member which means is disposed entirely below said lower annular member, and includes a driving element engaging the said lower annular member, power supply means passing through said base, and means for supporting said lower support member including a plurality of spaced bearings disposed below said lower annular member, said supporting means being operatively connected to said base, the lower lip of said casing lying below said lower support member, whereby the only elements above said lower annular support member which are movingly engaging comprise said workholders which roll along said second annular member and along said sunwheel, and whereby said workholder and said two support members are accessible on removal of said casing from said base.

7. The apparatus of claim 6 wherein each said workholder is a planetary member.

8. The apparatus of claim 1 wherein the peripheral edge of said stationary sun-wheel is noncircular relative to the axis of rotation of said second annular support member so that as said workholder rotates and moves around the periphery of said annular upper face of said second annular member the upper edge of said workholder rises and falls thereby changing the attitude of said workholder.

12. The apparatus of claim 1 wherein said work-holder comprises a subsidiary planet forming a subsidiary epicyclic system, said subsidiary planet including means for mounting a workpiece.

13. The apparatus of claim 12 wherein said workholder comprises an annulus and said subsidiary planet is rotatable relative to said annulus, means including both said annulus and said subsidiary planet for supporting a plurality of workpieces, and means for preventing absolute rotation of said rotatable member as said annulus rotates.

14. The apparatus of claim 1 which comprises two stationary sun-wheels one above the other and so positioned that the upper edge of said workholder may be inclined selectively against the peripheral edge associated with either of said stationary sun-wheels, each of said stationary sun-wheels providing thereby a different angle of inclination of the workpiece as the workpiece revolves about the upper annular face of said lower annular member.

15. The apparatus of claim 1 which includes at least one rotary spider having arms which extend between said workholders to avoid direct contact therebetween, each of said spiders being freely rotatable about the axis of rotation of said lower annular support member.

16. Apparatus for use in the vacuum deposition of workpieces comprising: means for defining at least in part a vaccum chamber, a lower annulaR support member rotatable about an axis perpendicular to its plane, at least two sun-wheels supported at varying distances above said lower annular support member and each defining a peripheral edge, at least one disc-shaped workholder, support means for said workholder including means for supporting an edge of said workholder and further including the peripheral edge of a selected one of said sun-wheels also supporting the edge of said workholder, and means for revolving said workholders in planetary fashion about said annular support member with the angle of inclination of each said workholder relative to the axis of rotation of said lower support member being dependent upon which of sun-wheels is in engagement with the edge of said workholder.