US2906906A

US2906906A - Indicator tubes

Info

Publication number: US2906906A
Application number: US737036A
Authority: US
Inventors: John H Mccauley; John R Bethke
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1958-05-22
Filing date: 1958-05-22
Publication date: 1959-09-29
Anticipated expiration: 1976-09-29
Also published as: GB925542A

Description

Sept. 29, 1959 J, H, Mc Y r 2,906,906

INDICATOR TUBES Filed May 22, 1958 m m v A M R O T m s F- R Pig. 4

IIIII INVENTOR. JOHN H Ma C/IULE) BY JOHN R. BETHAE ATTORNEY United States PatentO INDICATOR TUBEQ John H. McCauley, Elizabeth, and John R. Bethke, Martinsville, N.J., assignors to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Application May 22, 1958, Serial No. 737,036

' 8 Claims. c1. sis-109.5

This invention relates to gaseous indicator glow tubes and, particularly, to tubes of this type which contain a plurality of indicating glow cathodes.

Tubes of the type contemplated by the present invention are particularly suited for use with circuits which utilize binary principles of operation. Binary counters which use a series of interconnected flip-flop circuits are of this type. Such decade counters generally employ a matrix for translating a signal representing a binary number to a signal representing a decimalor other number equivalent of the binary number. Up to the present time, counters of this type have not had a completely satisfactory arrangement for providing direct readout of a count made by the counting circuit.

Accordingly, one object of the invention is to provide an improvedcathode indicator glow tube.

Another object of the invention is to provide an improved cathode indicator glow tube particularly suited for use in conjunction with binary-type counting circuits and, for providing a direct visible readout therefrom.

In brief, the principles and objects of the invention are embodied in a tube which comprises a gas-filled envelope containing a plurality of cathode glow electrodes. If, for example, the tube is to be used in a decade counter, it contains cathodes in the form of numerals to "9. The cathode glow electrodes are arranged in groups with each group having its own anode and with the groups separated from each other by a suitable barrier or shield. For use in a binary-coded system, the cathode electrodes are arranged in v two groups with theodd-number electrodes in one group and the even-number electrodes in the other group. Other combinations of cathode electrodes may be made as required bya particular code or circuit application. In addition, more than two groups of electrodes may be provided so that a simultaneous readout of a plurality of characters may be achieved.

In operation of a tube of the type described above, a

2,906,906 Patented Sept. 29, 1959 embodying the invention adapted to provide a multiple numeral readout.

Referring to the drawings, one form of a gaseous indicator glow tube 10 embodying the invention includes an envelope 12 which has been evacuated of air and filled with an ionizable gas such as neon or the like at a suit able pressure, for example, in the range of about to about 120 mm. Hg. The envelope includes a base portion or stem 14 through which insulation-coated metal base pins 16 extend and by means of which electrical connection is made to suitable external electrical circuit elements. Two diametrically opposed pins 16 are suitably elongated to receive and support the various electrode elements of the tube. The envelope 12 also includes a transparent viewing window 20'through' which glowing indicator cathode electrodes 22may be viewed. The viewing window may be plane or curved and'is oriented substantially transverselyto the vertical or longitudinal axis of the tube. A sealed-off exhaust tubulation (not shown) is provided in the stem 14. i

The electrode elements of the tube include the following. A generally cup-shaped electrode 24 is provided to contain the other electrode elements. Thecup-shaped electrode 24 is made of conductive or non-conductive material, depending on how it is to be used, and may be imperforate, in mesh form, or in any other suitable form. The cup electrode serves to shield the cathode electrodes 22 and to limit cathode glow to the main viewable body portions of the cathode numbers them selves. The cup also prevents the cathode pins and connecting leads from glowing spuriously and from having metal sublimed thereon. The cup electrode 24 includes a base 26 and a peripheral wall '28. The base 26 is oriented transverse to the longitudinal axis of the tube 10. The cup 24 rests on, and is insulated from, the pins 16 by an insulating disk 30 of mica or the like. The pins 16' pass through suitable apertures in the baseof I the cup and in the mica disk. Although the cup24 is a I are shown in Fig. 1.

single cathode in a group. may be, caused to glow by the application of the proper energizing voltage between the selected cathode and the anode associated with this cathode. The shield prevents interaction between the groups of electrodes and spurious glow of a cathode other than the selected cathode.

According to another aspect of the invention, multiple groups of cathodes are provided in a single envelope and are electrically connected so that a plurality of cathodes may be caused to glow at the same time to provide a multiple numeral readout.

The invention is described in greater detail by reference to the single sheet of drawings wherein:

Fig. 1 is a perspective view of a tube embodying the invention;

desirable tube element, it is not required, and the tube 10 may be made to operate without it. I

The cathode indicator electrodes 22 of the tube 10 may take substantially any desired shape; for example; they may be numbers, letters, or the like. In one form of the tube 10 wherein the cathode elements are numbers, ten of such elements are provided, including the numbers 0 to "9. These are shown schematically in Fig.2. For purposes of simplicity, only two cathodes The cathode elements 22 are made of any suitable metal, for example, stainless steel, alumif num, Nichrome, molybdenum, or the like; and they may be made in any suitable fashion, for example, by etching, stamping, formed wire, or the like.

The cathode electrodes 22 are mounted in a vertical stack having a vertical axis and are oriented substantially 7 material and are suitably displaced laterally with respect Fig. 2 is a schematic representation of the tube of Fig. 1 E

1 and a circuit in which it may be operated;

Fig. 3 shows the tube of Fig 2 and a schematic representation of a system in which i-tmay be used; and

Fig. 4 is a schematic representation or 'a modified tube to each other so that each one is not obstructed by the others and each is substantially completely visible through tabs *32 (only one is shown), at least two in number.

The tube shown in Fig. 1'

and oriented diametrically opposite each' other, by means of which the cathodes are mounted and supported on the pins 16. Each cathode is provided with a suitable lead wire (not shown) extending from one of the apertnred tabs thereof to one of the pins 16 within the envelope. One group of cathodes, for example, the odd-numbers, is rriollnted'first on the pins or posts 16'; These cathodes are mounted one above the other with their surfaces oriented parallel to each other and transverse to the vertical' axis ofthe tube and facing the viewing end of the envelope. The cathodes are mounted with suitable insulating spacers 34 between each one, the spacers being larger than theapertured tabs and having sufficient surface area' to cover and insulate the tabs to prevent them from glowing.

Next, three

screen electrodes

36, 38, and 40 are mounted above the odd-number cathodes, the screens being parallel to. each other and insulated f rom each other by suitable insulating spacers 34. The screens also have suitable apertured tabs for mountingon the pins 16' and lead wires for making suitable electrical connections to pins 16. The first screen 36 comprises an anode for the odd-number cathodes, and the third screen 40. is an anode for the even-number cathodes. The middle screen 38 is a shield which separates the two groups of electrodes from each other. The even-number cathodes are mounted above the anode screen 40, and finally a top screen 42 caps the stack of electrode elements. The top screen is used to prevent sublimation of metal from the cathodes onto the viewing window 20 which might thereby become opaque.

If the. tube 10' is to be used in a binary-type decade counter using flip-flop circuits, then the cathodes are connected together in pairs, the pairs comprising, for example, zero and one, two and three, four and five, six and seven, eight and nine. The, interconnections may be made in any suitable fashion; for example, each cathode 22 may be connected to a pin 16 and the appropriate pins may be connected together inside the envelope or outside the envelope. In another arrangement, the leads from each two cathodes to be connected together may be secured directly to the same pin inside the envelope. In another arrangement, the socket to be used with the tubes may be wired to provide the desired cathode pairs.

Each

anode screen

36 and 40 is connected to its own pin lead 16, just as the cathodes are. The shield screen electrode 38 may also be connected to a pin 16 and may be operated electrically neutral or at some suitable po tential. The cup 24 may also be operated either neutral or it may be connected to the shield screen 38 and thus operated at the same potential as this screen. The top screen 42 may be connected to the shield screen 38 to be operated at the same potential as the screen.

A schematic representation of the tube 10 and a typical circuit for operating it is shown in Fig. 2. In the circuit, the appropriate cathode numbers 22 are shown connected together in pairs, the pairs, in this instance, comprising zero and one, two and three, four and five, six and seven, eight andnine. The circuit also includes a selector switch 44 having five fixed switching elements or contacts 46 and a'movable contactor 48 adapted to engage any of the fixed contacts. The selector switch may be a mechanical or electronic switch controlled or driven from a keyboard, from a circuit matrix; associated with a counter, or it may be driven in any other suitable manner. Each pair of cathodes'is connected to one fixed contact of the switch 40. Each

anode

36 and 40 is coupled to a suitable positive DC. power supply in the range of about 100 volts to about 300 volts. The shield screen 38 may be biased from ground to about 100 volts positive.

In operation of the circuit of Fig. 2, as each pair of cathodes 22 is connected into an active circuit by the contactor' 48, one of the cathodes of each pair glows, depending on whi h a od is en g y t c cathodes 22', anodes 36' and 40' and a shield 38.

4 Thus, the even-number cathodes glow when anode 40 is energized, and the odd-number cathodes glow when anode 36 is energized.

A typical binary-coded decimal counter system 49 in which the tube 10 may be employed is shown in block diagram in Fig. 3. Thec'ounter shown includes four

flipflop circuits

50, 52 54, 56. connected to provide a typical counting operation. Input pulses are fed into the first flipi-fiop. circuit 50, and the output of thefirst fiip-fiop' is connected both intothecountingchain and to the

anodes

36 and 40 of the tube 10. The output lines of the flip-

flop circuits

52,54, and 56 are fed into a suitable selector matrix 58where the numerical count is determined and the output of the matrix is applied tothe' proper cathode of the tube. Thus, in essence, the output of the matrix energizes a particular cathode in a pair and the flip-flop 50 energizes a particular anode so that the proper cathode of the pair is ignited.

The principles of the invention may also be embodied in a tube which includes more than two sections or groups of electrodes. Such a tube 10' is shown schematically in Fig. 4 and comprises, in effect, two tubes of the type shown in Fig. 1 in the same envelope. The tube 10' com prises one set of electrodes 60 including the electrodes shown in Fig. 2 and a second set of electrodes 62 which may be arranged similarly to the first set and includes The tube 10' may be operated so that one cathode in each set glows at the same time and, thus, a two-numeral readout is achieved.

What is claimed is:

1. An indicator tube comprising a first indicator cathode adapted to glow and a second indicator cathode adapted to glow, an anode associated with each of said cathodes, and a shield electrode between each of said cathodes and its associated anode.

2. The tube defined in claim 1 wherein all of the electrodes are aligned in a common stack.

3. The tube defined in claim 1 wherein said cathodes are electrically connected.

4. An indicator tubecomprising a-first group of indicator cathodes adapted to glow and a second group of indicator cathodes adapted to' glow, an anode associated with each of said groups of cathodes, and a shield electrode between each of said groups of cathodes and its associated anode.

5. The tube defined in claim 4 wherein all of the electrodes are oriented parallel to each other and aligned in a common stack.

6. An indicator tube comprising a first stack of indicator cathodes adapted to glow, an anode electrode at the top of said first stack, a second stack of indicator cathodes adapted to glow, an anode electrode at the bottom of said second stack, said stacks being aligned with each other, and a shield electrode between said anodes.

7. The tube defined in claim 6 and wherein each cathode in said first stack is electrically connected to a cathode in said second stack. v I

8. An indicator tube comprising a plurality of electrode assemblies, each of said assemblies including a first indicator cathode adapted to glow and a second indicator cathode adapted to glow, an anode associated with each of said cathodes, and a shield electrode between each of said cathodes and its associated anode.

References Citedin the file of this patent UNITED STATES PATENTS 2,142,106 Boswau Jan. 3, 1936 2,606,309 Townsend Aug. 5, 1952 2,717,334 Desch Sept. 6, 1955 2,756,366 Maynard July 24, 1956 2,769,939 Williams Nov. 6, 1956 2,790,110 ,Applegate Apr. 23, 1957