US2795032A - Electro deposited grids for cylindrical type cathodes - Google Patents

Description

June ll, 1957 D. R. KERs-rE'rTl-:R 2,795,032 ELECTRO DEPOSITE GRIDS FOR CYLINDRICAL. TYPE CATHODES l Filed oct. 12, 195s IWA/DOW Q/Conr cur E] 40m/FR @.1 nar/N6 cum/v6 INVENTOR DONALD R. KERSTETTER Anog .trical characteristics. control grid of a radio tube it has been found difficult tube, all'withina very smallV Space.

vbeen lacquered.

structure, taken along the line6-6 of Fig. 5.

vfed into a stamping machine to have windows such as ELECrRo DErosrrEnonrDs ron cYLrN'- DRrcAr. TYPE cA'rrronEs Donald Kerstetter,l Emporium, Pa., assigner .to Syl- Vania Electric Products Inc., a corporation Aof Massa- Application October 12, v1953, Serlal'No.'l38 5,584 1.0

schim. (Caza-25.11)

This invention relates to grids and to the processof '15 making the same. '1

In themanufacture of radio tubes of very small size,

. it has been found dicult to' make the conventionally/ wound grids of a size commensurate with the rest of the electrodes in the vtube and yet secure the desired 'elec- Particularly in the case of the to obtain a small sized grid which. shallyet have an ex-` cellent control function on the electron tube. A It is desirable to make the grid small, of tinel mesh and-very thin to'cause the tube'to have a high .transconductance and to allow for' positioning of other' electrodes in the An object of this' invention, therefore, is to provide such agrid.

A further object is to this grid. .l

For a full disclosure of the invention, attention is -directed Ito the following description and accompanying drawing, in which:

`Fig.1 is a block tiowdiagram of a process of making grids in 'accordance with my invention.

Fig. 2 is'a viewv of metallic strip with windows cut out in which the grid formation is to appear.

Fig. 3 is a similar view after one side of the strip has providea method for forming Fig. 4 is a view o f a film with a metallic design imprinted thereon.y

Fig. 5 is a view of the apertured metallic strip lacquered on the top lface and covered with .the film of Fig. 3 on '45 the lower face, the-film `having its metallic design on Fig. 7 is a view of the same jected to a plating bath. l

Fig. 8 is a view of a modified form of grid. Fig. 9 is a crossA section through a grid made in accordance with my invention, and

Fig. l0 is .a perspective view of a number ofv grids during the process of their manufacture.

Referring more in detail to the figures, acontinuous portion after being sub- `strip of metal l, such as nickel .001" to .002" thick and a width to .be vthe height of the grid in a radio tube, is

00 windows 3 in Fig. 2 formed in the strip. These windows are subsequently to be filled in with a metallic lattice work. of a suitable design to exercise the control function ofa gridin a radio tube.

The apertured nickel stri'p is then coated on one side, asy the upper surface, with a non conductive coating such as lacquer 5, to prevent subsequent plating materials from being deposited on that surface.

The opposite surface of the strip, either simultaneously with this coating operation or subsequently thereto, has applied to it a fil'm, such as an acetate film 7, having imprinted thereon an electroconductive lattice work 9 .at least over areas which hesive.

2,795,032 l Patented June 11,l 1957 would coincide with the windows 3 rn the strip. In the simplest form of my invention, the lattice work appears. on the entire facev of the film. The film may be made to adhere to the nickel strip m any desired manner as simply 'by pressing the film hard against the nickel strip, driving out occluded air between the imprinting and the nickel strip or'by coating the lower surface of the nickel `strip with some form of ad- After the nickel strip has had the lacquer coating and imprinted vacetate film associated with it, the laminated K "structure would appear as indicated diagram-matically in Fig. A5 and in cross section in Fig. 6. The design of the imprintings on the acetate film is then visible through the windows. The laminated strip is then fed slowly through a nickel plating bath, see Figrl, the speed of Ithe strip and the current strengthbeing adjusted so as to deposit on the imprinted design appearing in the win- .dows an amount of nickel 11 to bring the same almost to the level of the upper surface of the nickel strip. In

' this process, also, the electro deposited material bonds in with the adjacent window walls of the nickel strip.

If desired the laminated structure may, after passing through a rinse, as a rinsing bath, be passed through further rinsing and plating baths to cause a deposit of gold plate to appear on the nickel deposit lattice work. `After plating theJst-rp as described above, the formed stripis passed through another rinse or rinsing bath to remove the plating solutions, then successively through a 4Aample of the type disclosed in Kershaw 2,064,169 to form series connected grids 13 mounted on support rods 14 lwhich may be cut up into individual grids by cutting the l connected grids between pairs of support rods 14, see

Fig. 10. If desired the laminated strip may be cut between pairs of windows and the strip bent around support rods 15 as indicated in Fig. 9with the window portions facing each other.

In Fig. 8, instead ofthe lattice work being close and of diagonal formation, it is shown as forming .arge square openings 16, since in some operations a grid work of this type is more desirable than that shown in Fig. 4.

Having thus described the invention, what is claimed as new is: l. In the method of making grids, the steps of applying to a surface of an apertured metallic'strip a layer of material -having grid-work conductive design portions exposed through the apertures in the strip, and plating the so exposed portions to build up the level of the design to a desired thickness in the. strip and to bond the plating to the strip.

2. In the method of making grids, the steps of applying to a surface of an apertured metallic strip, a non conductive supporting layer having a conductive gridwork design on one surface, with the design exposed grid work in the apertures and bond the grid-work to the'. metallic strip, and removing the non conductive portron of the supporting layer.

4. In the method of making grids, the steps of apply- I ing to a surface of an apertured metal strip, an acetate lm having a conductive grid-work design exposed through thc apertures in the metal strip, plating the so exposed grid-work, said plating effecting bonding of the .grid-work to the adjacent walls of the strip, and removing the` acetate film from the nickel strip while leaving the gridwork in the metal strip.

5.-ln the method of forming grids, the steps of apply-V strip, and removing the non conductive portion of the supporting layer.

6. In the method of making grids, -the steps of applying to one surface of an apertured strip a non conductive film bearing a conductive imprint thereon of a gridwork design, with the design exposed through the aperturcs, plating the so exposed design to build.up the thickness of the conductive imprint totsubstantially the upper face of the metallic strip and to bond the plated- 4 material to the strip, and removing the film to leave the gridwork design as an integral portion of the strip.

7. In the method of making grids, the steps o f apply; ing a non conductive coating'to one surface of an apertu'red conductive strip, applying .a non conductive lm bearing 'a conductive grid-work imprint thereon to the other surface of the strip, with'the imprint` exposed through the aperturesplating the sel exposed imprint to build up the thickness thereof as a grid-work to substantially the upper face of the metallic Vstrip and to bond the plated material to the strip,- and removing the'lm to leave the grid-work as an integral portion of the strip.

` 8. In the method of making grids, the steps of applyl ing a non conductive coating to onel surface Aotan apertured conductive strip, applying a non conductive film hearing a conductive imprint thereon to the other surface of 'the strip, with the imprint exposed through they'apern tures, 'plating the so exposed imprint to build up the Vthickness thereof as a grid-work to substantially the upper face of the metallic strip and to bond the plated material to the strip1 and removing the non conductive coating and film to leave the grid-work as an integral portion of the strip'.

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