US3794881A - Supply circuit for a gas discharge character display tube - Google Patents

Supply circuit for a gas discharge character display tube Download PDF

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Publication number
US3794881A
US3794881A US00217593A US3794881DA US3794881A US 3794881 A US3794881 A US 3794881A US 00217593 A US00217593 A US 00217593A US 3794881D A US3794881D A US 3794881DA US 3794881 A US3794881 A US 3794881A
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United States
Prior art keywords
cathode
cathodes
tube
circuit
common
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Expired - Lifetime
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US00217593A
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English (en)
Inventor
D Janssen
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US Philips Corp
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US Philips Corp
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/04—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions
    • G09G3/06—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions using controlled light sources
    • G09G3/10—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions using controlled light sources using gas tubes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K21/00—Details of pulse counters or frequency dividers
    • H03K21/08—Output circuits

Definitions

  • ABSTRACT A supply circuit for agas discharge character segment display tube in which the cathode circuit of one or more cathodes luminescing upon the display of each character includes a measuring resistor from which a control voltage is derived for a supply voltage control.
  • the invention relates to a supply circuit for a gas discharge character display tube having at least one anode and at least two cathodes cooperating with said anode, said supply circuit including a stabilised current source circuit for supplying an electrode of the gas discharge character display tube with a substantially constant current, said stabilised current source circuit including a measuring resistor across which a voltage is maintained constant by the stabilised current source circuit by controlling an anode supply voltage.
  • a supply circuit of the kind described above is known from Philips Application Information 334 for a gas discharge character display tube in which the cathodes in the area of contact with the gas in which the discharge takes placehave the shape of a character to be displayed.
  • An object of the present invention is to provide a supply circuit for a different type of gas discharge display tube.
  • a supply circuit of the kind described in the preamble is characterized in that the gas discharge character display tube is a character segment display tube with which segments of characters can be displayed by means of a plurality of cathodes while the measuring resistor is arranged in a cathode circuit of a cathode which is common to different characters, and which is, optionally, shielded from visual observation.
  • character segment tubes exhibit a small spread in cathode current density at a given anode voltage. Stabilisation of the current of a cathode which for a plurality of characters to be displayed must luminesce as a section of these characters is found to be a surprisingly favourable replacement of the anode current stabilisation which for these types of tubes would produce a luminosity which is different from character to character. r
  • FIG- URE illustrates by means of a non-detailed circuit diagram a supply circuit according to the invention for a multiple character segment tube.
  • a gas discharge multiple matrix character segment display tube 1 has a plurality of anodes 3, and 7 and cathodes cooperating therewith in which only the cathodes facing anode 3 have reference numerals 9, 11, 13 and 15. Corresponding cathodes facing the other anodes are interconnected to these cathodes.
  • the anodes 3, 5 and 7 are connected through pnp transistors l7, l9 and 21 to the positive terminal (-H-) of a controlled supply source 22 which serves as a stabilised current source circuit.
  • the bases of transistors l7, l9 and 21 are connected to a decoder circuit 23 having input lines 25 which receive signals that relate to a desired character to be displayed.
  • the cathodes 9, l1, l3 have the shape of a section or segment of a character to be displayed and they are each connected through resistors 27, 29, 31 and 33, respectively, to the negative terminal of a supply source 35 which produces a voltage of, for example, 25 Volts.
  • cathodes 9, 11, 13 and 15 and resistors 27, 29, 31 and 33 are applied through pnp transistors 37, 39, 41 and 43, respectively, to a positive terminal of supply source 35.
  • the bases of these transistors are connected to the decoder circuit 23.
  • transistor 37, 39, 41 and 43 those transistors are cut off whenever the cathodes connected to their collectors must luminesce.
  • the area opposite the anode where the relevant cathode is to luminesce is determined by the conductance of one of the transistors 17, 19 or 21.
  • connections between cathodes 11 and 15 and resistors 29 and 33 are applied through diodes 45 and 47, respectively, to a control input 49 of the controlled supply source 22.
  • Cathodes 11 and 15 are cathodes which are common to a plurality of characters to be displayed. At least one of these two cathodes luminesces for all characters to be displayed. The voltage drop across resistor 29 or 33 is then low and one of the diodes 45 or 47 conducts.
  • the collector of transistor 51 is connected through a winding of a transformer 57 and a resistor 59 to the base of an npn transistor 61.
  • the collector of transistor 51 is furthermore decoupled with respect to alternating voltage through a capacitor 62.
  • Transistor 61 and transformer 57 constitute a voltage converter circuit which converts a direct voltage supplied by supply source 35 into an alternating voltage of a higher value which is rectified through a diode 63 and is smoothed by a capacitor 65 and which provides a high direct voltage for the (-ii-) terminal of supply source 22.
  • the collector current of transistor 51 which current is dependent on the voltage across resistor 29 or 33
  • the voltage at the (-ll-) terminal is controlled in such a manner that the voltage across this resistor 29 or 33 is maintained substantially constant and hence the current flowing to the relevant cathode.
  • Resistors 27, 29, 31 and 33 are chosen to be preferably such that the current density for the relevant cathodes becomes substantially equal and they must then be chosen dependent on the surface of the relevant cathode.
  • the voltage drop across these resistors generally need not be larger than approximately 5V.
  • a gas discharge character multiple section display tube is shown, Le, a tube which is suitable for the substantially simultaneous display of a plurality of characters. Examples of this type of tube are illustrated in U.S. Pat. No. 3,418,509, 3,731,132 and 3,6l9,694. lt is alternatively possible to use a separate tube for each character to be displayed.
  • the gas discharge character segment display tube may be of a type equipped with control grids.
  • the pnp transistors 37, 39, 41 and 43 may alternatively be p-channel MOS transistors which may be incorporated in an integrated circuit.
  • the various cathodes may be ignited with the aid of transistors arranged in series with the resistors 27, 29,
  • a display system comprising a gas discharge character segment display tube in which segments of characters can be displayed by means of a plurality of cathodes, said display tube comprising a plurality of electrodes including at least one anode electrode and at least two cathode electrodes cooperating with said anode, at least one of the tube cathodes being common to different characters to be displayed, and a stabilised current source circuit for supplying the tube anode voltage and one of said cathodes of the gas discharge character display tube with a substantially constant current and including a measuring resistor connected in the cathode circuit of said common cathode, said current source circuit being responsive to a voltage de veloped across said resistor for controlling the tube anode supply voltage so as to maintain the voltage across the resistor constant.
  • gas discharge character segment display tube is of the multiple matrix type for the substantially simultaneous display of a plurality of characters and having a common cathode for each character, and means for coupling the common cathodes through a gating circuit to a control input of the stabilised current source circuit.
  • a display system comprising a gas discharge character segment display tube, said tube comprising a plurality of electrodes including at least one anode electrode and a plurality of cathode electrodes cooperatively disposed to said anode, at least one of the tube cathodes being common to different characters to be displayed, a regulated source of current having output terminals coupled to the tube electrodes to supply operating voltages across the tube anode-cathode circuits,
  • a measuring resistor connected in the cathode circuit of said common cathode across which a control voltage is derived from the current supplied by said regulated current source, and means for applying said control voltage to a control input terminal of the regulated current source, said regulated current source including means responsive to said control voltage for controlling the tube operating voltage in a manner to maintain the voltage across said resistor substantially constant whereby at least one electrode of the display tube draws a substantially constant current from the regulated current source.
  • a display system as claimed in claim 6 further comprising a plurality of resistors each individually connected to a given one of the cathodes of said display tube, at least one other of said tube cathodes being common to the different characters to be displayed, and a diode gate circuit for coupling the common cathodes to the control input terminal of the regulated current source.
  • a display system as claimed in claim 8 wherein at least one cathode of the second group of cathodes is common to the different characters to be displayed and includes a measuring resistor in the cathode circuit thereof for deriving a control voltage, and a gating circuit for coupling all of said common cathodes to the control input of the regulated current source.
  • a display system as claimed in claim 6 wherein the display tube includes an auxiliary cathode shielded from view and common to the different characters to be displayed, and wherein said measuring resistor is connected in the cathode circuit of said auxiliary cathode.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Gas-Filled Discharge Tubes (AREA)
US00217593A 1971-01-29 1972-01-13 Supply circuit for a gas discharge character display tube Expired - Lifetime US3794881A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7101186A NL7101186A (xx) 1971-01-29 1971-01-29

Publications (1)

Publication Number Publication Date
US3794881A true US3794881A (en) 1974-02-26

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ID=19812360

Family Applications (1)

Application Number Title Priority Date Filing Date
US00217593A Expired - Lifetime US3794881A (en) 1971-01-29 1972-01-13 Supply circuit for a gas discharge character display tube

Country Status (8)

Country Link
US (1) US3794881A (xx)
JP (1) JPS5316653B1 (xx)
CA (1) CA953003A (xx)
DE (1) DE2200637C2 (xx)
FR (1) FR2124885A5 (xx)
GB (1) GB1381167A (xx)
IT (1) IT951107B (xx)
NL (1) NL7101186A (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3883775A (en) * 1973-01-08 1975-05-13 Philips Corp Gas discharge display system with current suppression means
US4109180A (en) * 1977-06-23 1978-08-22 Burroughs Corporation Ac-powered display system with voltage limitation
US4250504A (en) * 1979-08-23 1981-02-10 General Electric Company Gas discharge display circuit

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4024429A (en) * 1975-10-06 1977-05-17 Panel Technology, Inc. Operating voltage supply system for gas discharge display panel
DE2701303C3 (de) * 1977-01-14 1983-02-17 Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen Hydraulische Zahnradmaschine
JPS54181642U (xx) * 1978-06-10 1979-12-22
US4347509A (en) * 1980-02-27 1982-08-31 Ncr Corporation Plasma display with direct transformer drive apparatus
JPS5984193U (ja) * 1982-11-30 1984-06-07 松下電工株式会社 窓の気密構造

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3307171A (en) * 1962-07-03 1967-02-28 Philips Corp Apparatus for energizing an electrical load device
US3414764A (en) * 1965-03-15 1968-12-03 Sony Corp Circuit for controlling the displaying of selected indicia by indicator tubes in a display system for electronic computers and the like
US3581065A (en) * 1966-12-02 1971-05-25 Hitachi Ltd Electronic display system
US3614524A (en) * 1969-04-03 1971-10-19 Sony Corp Display system with different intensity indication
US3679933A (en) * 1968-12-23 1972-07-25 Sony Corp Display system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3307171A (en) * 1962-07-03 1967-02-28 Philips Corp Apparatus for energizing an electrical load device
US3414764A (en) * 1965-03-15 1968-12-03 Sony Corp Circuit for controlling the displaying of selected indicia by indicator tubes in a display system for electronic computers and the like
US3581065A (en) * 1966-12-02 1971-05-25 Hitachi Ltd Electronic display system
US3679933A (en) * 1968-12-23 1972-07-25 Sony Corp Display system
US3614524A (en) * 1969-04-03 1971-10-19 Sony Corp Display system with different intensity indication

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3883775A (en) * 1973-01-08 1975-05-13 Philips Corp Gas discharge display system with current suppression means
US4109180A (en) * 1977-06-23 1978-08-22 Burroughs Corporation Ac-powered display system with voltage limitation
US4250504A (en) * 1979-08-23 1981-02-10 General Electric Company Gas discharge display circuit

Also Published As

Publication number Publication date
JPS5316653B1 (xx) 1978-06-02
CA953003A (en) 1974-08-13
IT951107B (it) 1973-06-30
DE2200637C2 (de) 1982-05-27
FR2124885A5 (xx) 1972-09-22
NL7101186A (xx) 1972-08-01
GB1381167A (en) 1975-01-22
DE2200637A1 (de) 1972-08-17

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