US3617803A - Raised-cathode gas discharge indicator having a sputter shield - Google Patents
Raised-cathode gas discharge indicator having a sputter shield Download PDFInfo
- Publication number
- US3617803A US3617803A US876618A US3617803DA US3617803A US 3617803 A US3617803 A US 3617803A US 876618 A US876618 A US 876618A US 3617803D A US3617803D A US 3617803DA US 3617803 A US3617803 A US 3617803A
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- US
- United States
- Prior art keywords
- substrate
- cathode
- pins
- pin
- diameter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J17/00—Gas-filled discharge tubes with solid cathode
- H01J17/38—Cold-cathode tubes
- H01J17/48—Cold-cathode tubes with more than one cathode or anode, e.g. sequence-discharge tube, counting tube, dekatron
- H01J17/49—Display panels, e.g. with crossed electrodes, e.g. making use of direct current
- H01J17/491—Display panels, e.g. with crossed electrodes, e.g. making use of direct current with electrodes arranged side by side and substantially in the same plane, e.g. for displaying alphanumeric characters
Definitions
- a gas discharge indicating device comprising a plurality of symbol-forming cathode elements disposed intermediate a cathode-supporting substrate and a transparent anode connected to one another in a manner to form a hermetically sealed enclosure for containing an ionizable gas, the cathode elements being supported in spaced relation to both the anode and substrate on pins passing through the latter.
- An insulating shield is provided on each support pin proximate the substrate preferably in noncontacting relation therewith.
- This invention relates to symbol indicators of the gas discharge type wherein symbols are represented by localized glow discharges between an anode member and selectively energized cathode elements of a plurality of such elements arranged to form various symbols. More, particularly, the invention relates to means for preventing or at least inhibiting the development of sputter-induced shorting contacts between individual cathode elements.
- That application relates to a gas discharge indicator comprising a cathode-supporting substrate overlaid by a transparent anode member to form a hermetically sealed enclosure containing ionizable gas.
- the cathode elements are supported in spaced relation to both the anode and the cathode-supporting substrate on pins passing through the substrate.
- Glow discharges representative of the symbols to be presented are produced by energizing appropriate cathode elements.
- the spacing of the cathode elements relative to both the anode and cathode-supporting substrate minimizes sputtering from the substrate side of the cathodes for a prescribed operating pressure of the ionizable gas in the hermetically sealed enclosure. This feature of reduced sputtering in combination with depressions formed in the interior surface of the substrate in the region of the pins passing therethrough retards the development of sputtered shorting contacts between the individual support pll'lS.
- the present invention is also directed to apparatus for reducing the formation of sputter-induced shorting contacts between the respective cathode-supporting pins of a raisedcathode gas discharge indicator, particularly in the depressed region of the substrate around or near the cathode supporting pins.
- an insulating shield typically a nonconductive washer, is placed on each cathode support proximate the substrate and preferably in nonconducting relation therewith. This configuration provides a means for protecting the depression around the cathode support pins from sputtered products although it will be understood that the shield of the present invention may be usefully employed in arrangements which do not include the depressions.
- FIG. 1 is a simplified exploded view in perspective of a typical embodiment of the invention.
- FIG. 2 is a section along line 2-2 of FIG. 1.
- glass substrate 1 is apertured to receive a number of electrical contacting pins 2 which are hermetically sealed to the substrate.
- the pins extend beyond both surfaces of the substrate so as to be adapted, at the ends beyond the rear surface of the substrate, for connection to a mating pin receptacle (not shown).
- individual cathode segments 3 are secured to the other end of the respective pins, for example, by welding, to form a conventional alpha-numeric symbol.
- the lengths of the individual pins are adjusted so that all of the cathode segments lie in approximately the same plane at substantially the same distance from substrate 1. it should be noted that additional symbols and other configurations can obviously be provided, if desired, simply by modifying the number, shape or position of the cathode segments and their associated contacting pins.
- Substrate l is also provided with an aperture 4 to which gas fill tube 5 is hermetically sealed on the side of the substrate opposite the cathode segments.
- a mercury ampule 6 is inserted inside tube 5.
- substrate 1 is equipped with an additional pair of hermetically sealed feed through pins 7 and 8 for establishing electrical contact to the anode member 9 of the gas discharge tube.
- the anode member comprises a glass substrate on which is deposited a thin film 10 of a transparent conductive material completely covering the interior surface facing substrate 1.
- Anode member 9 is spaced from substrate 1 by glass spacer plate 11 having a main aperture 12 defining a volume for enclosing and ionizable gas to produce cathode glows when the indicator is completely assembled and energized.
- Spring contacts 13 and 14 pass through a pair of apertures l5 and 16 to establish electrical contact from pins 7 and 8 to the conducting film surface 10 in the assembled unit.
- the thickness of the spacer plate 11 is determined by the anodecathode and cathode-substrate spacings required to cause only the anode side of the cathode elements to glow under a given gas pressure, taking into account, of course, the thickness of the cathode elements themselves.
- the spacer thickness is typically 0.040 inch and the cathode segments are spaced from the interior surface 17 of substrate 1 by approximately 0.005 inch.
- the spacing of the cathode segments from the cathodesupporting substrate can be obtained as explained in the aforementioned Armstrong et al. application by first inserting the pins 2 through substrate 1 so that the ends to be attached to the cathode segments lie flush with the interior surface of the substrate, then hermetically sealing the pins to the substrate and finally etching the interior surface of the substrate to the desired depth. The process is so controlled that a depression 19 is formed in the substrate surrounding the pins.
- a suitable etchant is a solution of distilled water and hydrofluoric acid.
- the cathode segments can be spaced from the substrate by adjusting the cathode-supporting lengths thereabove by any conventional mechanical technique.
- insulating washers 18 are slid over the pins and maintained thereon a short distance above the substrate, typically 0.001 inch to 0.003 inch in the illustrated embodiment as by gluing or by means of an abutment or shoulder on the pins.
- Any material suitable for use in the ionizable gas, such as glass, ceramic, mica or ceramic insulated metals, can be used for the washers.
- the washer thickness is'not critical.
- washers having a thickness in the range of 0.001 to 0.006 inch have a thickness in the range of 0.001 to 0.006 inch, but there is no apparent reason why thicknesses outside of this range would not also be suitable.
- the washer diameter must be suitable to isolate the desired area around each pin in a manner to achieve the aforedescribed mode of operation.
- a washer having a diameter of 0.060 inch, for example, has been found appropriate for use with a pin having a diameter of 0.020 inch.
- the washers should preferably have a diameter such that the difference between the washer diameter and pin diameter is at least twice as great as the separation between the support substrate and the cathode elements.
- the indicator is assembled by bringing elements 1, 9 and 1 1 into aligned contact with each other and hermetically sealing the entire edge surface of the aligned unit.
- Conventional techniques are applied for purging the atmosphere within the sealed unit and then filling and sealing the unit with an appropriate ionizable gasand the mercury contained in ampule 6.
- the mercury is released into the sealed gas atmosphere at a suitable time during fabrication as is well known in the art to provide therein an amount of this vapor to inhibit cathode sputtering by absorbing a significant amount of kinetic energy of the ionized gas particles before they bombard the cathode segments.
- construction of a gas discharge indicator in the described manner will essentially eliminate sputtering from the substrate side of the cathode segments, Moreover, sputtered material emanating from the anode side thereof will be effectively blocked by the washers to preclude the formation of shorting contacts between the individual support pins along the interior surface of substrate 1 thereby significantly lengthening the operational life of the indicator. Sputtered material may tend to collect on the upper surface 20 of the washer but electrical contact with the substrate will not be likely since differential temperature expansion and vibration of the various components will prevent the establishment of any permanent low-resistance connection therebetween.
- a gas discharge indicator comprising a hermetically sealed envelope containing an ionizable gas at glow discharge pressure, said envelope being formed at least in part by a cathode-supporting substrate,
- each of the pins passing through and hermetically sealed to the substrate such that one end of each of the pins extends beyond the interior surface of the substrate, the opposite end of each of the pins being adapted for connection to a source of electrical excitation for selectively energizing the respective pins,
- each support pin in closely spaced noncontacting relation with the interior surface of the substrate for further inhibiting deposition of sputter material adjacent each pin.
- the insulating washer members have a diameter such that the difference between the insulating member diameter and the pin diameter is at least a factor of two greater than the cathode-to-substrate spacing.
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- Gas-Filled Discharge Tubes (AREA)
Abstract
Description
Claims (3)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US87661869A | 1969-11-14 | 1969-11-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3617803A true US3617803A (en) | 1971-11-02 |
Family
ID=25368169
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US876618A Expired - Lifetime US3617803A (en) | 1969-11-14 | 1969-11-14 | Raised-cathode gas discharge indicator having a sputter shield |
Country Status (1)
Country | Link |
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US (1) | US3617803A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3704386A (en) * | 1971-03-19 | 1972-11-28 | Burroughs Corp | Display panel and method of operating said panel to produce different colors of light output |
US3716742A (en) * | 1970-03-03 | 1973-02-13 | Fujitsu Ltd | Display device utilization gas discharge |
-
1969
- 1969-11-14 US US876618A patent/US3617803A/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3716742A (en) * | 1970-03-03 | 1973-02-13 | Fujitsu Ltd | Display device utilization gas discharge |
US3704386A (en) * | 1971-03-19 | 1972-11-28 | Burroughs Corp | Display panel and method of operating said panel to produce different colors of light output |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: BECKMAN INDUSTRIAL CORPORATION A CORP OF DE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:EMERSON ELECTRIC CO., A CORP OF MO;REEL/FRAME:004328/0659 Effective date: 19840425 Owner name: EMERSON ELECTRIC CO., A MO CORP. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BECKMAN INSTRUMENTS, INC.;REEL/FRAME:004319/0695 Effective date: 19840301 |
|
AS | Assignment |
Owner name: DIXON DEVELOPMENT, INC., A CA CORP. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BECKMAN INDUSTRIAL CORPORATION;REEL/FRAME:004337/0564 Effective date: 19840928 Owner name: WALTER E HELLER WESTERN INCORPORATED Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DIXON DEVELOPMENT, INC. A CORP. OF CA.;REEL/FRAME:004337/0572 Effective date: 19840928 |
|
AS | Assignment |
Owner name: BABCOCK DISPLAY PRODUCTS,INC. Free format text: CHANGE OF NAME;ASSIGNOR:DIXION DEVELOPMENT,INC.;REEL/FRAME:004372/0199 Effective date: 19841002 |