US3815120A - Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits - Google Patents

Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits Download PDF

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Publication number
US3815120A
US3815120A US00269681A US26968172A US3815120A US 3815120 A US3815120 A US 3815120A US 00269681 A US00269681 A US 00269681A US 26968172 A US26968172 A US 26968172A US 3815120 A US3815120 A US 3815120A
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United States
Prior art keywords
cathode
group
cathodes
groups
anodes
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
Application number
US00269681A
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English (en)
Inventor
A Kanda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WALTER E HELLER WESTERN Inc
Sperry Corp
Microsemi Corp Power Management Group
Original Assignee
Sperry Rand Corp
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Filing date
Publication date
Priority to GB30633D priority Critical patent/GB30633A/en
Application filed by Sperry Rand Corp filed Critical Sperry Rand Corp
Priority to US00269681A priority patent/US3815120A/en
Priority to CA172,774A priority patent/CA977440A/en
Priority to AU57308/73A priority patent/AU466623B2/en
Priority to GB3063373A priority patent/GB1399581A/en
Priority to IT51243/73A priority patent/IT989747B/it
Priority to FR7324848A priority patent/FR2192372B1/fr
Priority to JP48076447A priority patent/JPS4960135A/ja
Priority to DE19732334539 priority patent/DE2334539A1/de
Priority to NL7309502A priority patent/NL7309502A/xx
Priority to SE7309541A priority patent/SE383662B/xx
Application granted granted Critical
Publication of US3815120A publication Critical patent/US3815120A/en
Assigned to BECKMAN INDUSTRIAL CORPORATION A CORP OF DE reassignment BECKMAN INDUSTRIAL CORPORATION A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: EMERSON ELECTRIC CO., A CORP OF MO
Assigned to EMERSON ELECTRIC CO., A MO CORP. reassignment EMERSON ELECTRIC CO., A MO CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BECKMAN INSTRUMENTS, INC.
Assigned to WALTER E HELLER WESTERN INCORPORATED reassignment WALTER E HELLER WESTERN INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: DIXON DEVELOPMENT, INC. A CORP. OF CA.
Assigned to DIXON DEVELOPMENT, INC., A CA CORP. reassignment DIXON DEVELOPMENT, INC., A CA CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BECKMAN INDUSTRIAL CORPORATION
Assigned to BABCOCK DISPLAY PRODUCTS,INC. reassignment BABCOCK DISPLAY PRODUCTS,INC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE OCT.12,1984 Assignors: DIXION DEVELOPMENT,INC.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K21/00—Details of pulse counters or frequency dividers
    • H03K21/08—Output circuits
    • 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

Definitions

  • the present invention relates to a novel time multiplex driver circuit for a multi-character cold cathode negative glow type gaseous discharge display device.
  • a cold cathode negative glow type gaseous discharge display tube typically comprises a hermetically sealed enclosure containing an ionizable gas at suitable pressure and respective anode and cathode electrodes disposed in the gas in relatively close spacing to one another. Either alternating or direct current electrical 'excitation may be used for operation of the tube. ln the case of direct current excitation, for example, application of an ionizing potential difference between an anode and cathode produces visible glow in a thin layer of the gas proximate and generally configured to the shape of the cathode which may be in the form of letters, nume'ralsor other symbols desired to be displayed.
  • Simultaneous presentation of multiple characters can be produced with either the stack or segmented array type tubes by using a plurality of either of such tubes disposed, for instance, in side by side relation so that a distinct character can be displayed at the location of each stack or segmented array.
  • One way in which such an arrangement of tubes may be activated is to connect all the anodes in parallel and connect each stack or segmented array to a separate cathode driver.
  • the individual cathode drivers typically include suitable logic and switching circuits for selecting the'individual shaped cathodes or cathode segments as the case may be. For a multi-character display, however, such as a multidigit number, it is apparent that the number of cathode drivers becomes quite large with this kind of driver arrangement.
  • anode strobing or time multiplexing techniques in which common cathodes of each stack or segmented array are connected in parallel and activated from a single cathode driver circuit, while the anodes of the respective stacks or arrays are energized sequentially.
  • a character is produced in the associated stack or array in accordance with the cathode or segments which are activated at the same time.
  • the anode strobing rate is made sufficiently fast commensurate with persistence of the ionized glow, and vision of the human eye so that all of the characters appear to be continuously energized without perceptible flicker.
  • each character mustbe energized for at least a prescribed minimum time to obtain a certain luminous intensity.
  • the required on-time for each character limits the number of characters which can be displayed for a given repetition rate, that is rate of successively energizing a discrete character of a multi-character display.
  • the necessity for a blanking interval further limits the maximum number of characters which can be displayed for a prescribed brightness and repetition rate.
  • a multi-character display is provided in a typical embodiment by the use of a plurality of indicator tubes each containing two anodes operatively associated with respective segmented cathode arrays.
  • anodes of each tube are connected in parallel for simultaneous electrical excitation sequentially with all of the other tubes.
  • the anodes of tube 1 are simultaneously energized then the anodes of tube 2, and so on, until all the tube anodes are energized and then the cycle repeats for as long as the characters are to be displayed.
  • one segmented array of each tube is coupled to one group of cathode drivers while the other segmented array of each tube is coupled to another group of cathode drivers.
  • the respective groups of cathode drivers are rendered operative alternately as a result of which during the interval that the anodes of each tube are energized an ionized glow display will be produced in succession at the respective segmented array positions of each tube, the shape of the glow being dependent on the cathode selected to be activated.
  • an ionization condition will be produced at one segmented array in one half of the time interval and at the other segmented array in the other half of the time interval and so on for each tube as its anodes are energized in sequence.
  • the repetition rate is made fast enough to provide for continuous presentation of all the characters of the display.
  • each tube has at least two segmented arrays or groups of cathodes and associated anodes but is not limited to any particular number of arrays or anodes.
  • FIGS. la and 1b are a schematic diagram illustrating a driver-circuit of the present invention interconnected with a plurality of gas discharge indicator tubes each containing two segmented cathode arrays and associated anodes.
  • FIGS. 2a 2lz are timing diagrams depicting waveforms useful in explainingthe operation of the circuit of FIG. 1.
  • FIG. 3 is a block diagram of a cathode driver circuit incorporating a latching feature which may be used in the apparatus of FIG. 1 for further enhancement of the display brightness.
  • FIGS. 4a-4f are timing diagrams depicting waveforms useful in explaining the operation of the apparatus of FIG. 1 when constructed with a cathode driver as shown in FIG. 3.
  • the driver circuit of the present invention will be described with regard to display apparatus including a plurality of cold cathode negative glow gaseous discharge indicator-tubes a, 10b NM.
  • the respective tubes are essentially identical in construction and typically comprise a hermetically sealed enclosure containing an ionizable gas at suitable pressure and formed at least in part of a transparent material to enable viewing of the characters disposed which is to be displayed, the numbers of tube ltla' representing the two least significant digits, and those of tube lOn representing the two most significant digits of the displayed number.
  • each tube contains a pair of anodes 11a, 11a" and respective associated groups of cathodes 12a, 12a, the individual cathodes of each group are further designated with the letters a-g.
  • Respective anode drivers 13a. 13b l3n are coupled to the anodes of the individual tubes 10a, 10b in.
  • each such driver includes a pnp transistor having its emitter connected to the positive terminal of a voltage source 8+ and its collector connected in parallel to the anodes of the associated indicator tube.
  • First and second groups playing the desired number at each digit position.
  • Each group of cathode drivers has seven output leads also designated by the letters a-g for coupling to the correspondingly designated cathode segments of the cathode arrays in such a way that the output leads of driver group 14' connect to the least significant digit cathode group l2a, to cathode group 12b of tube 10b and so on to alternate groups of cathodes so as to be connected finally to'cathode group 12n' of tube l0n.
  • each such driver element comprises an npn transistor having its collector connected to an individual output lead of the driver group in which it is incorporated whileits emitter is coupled through a resistor to the collector of an npn transistor comprising odddigit switch 15', the emitter of the latter in turn being connected to ground 16.
  • the driver elements of driver group 14 are similarly constructed and each in turn connected to an even-digit switch 15" which is also returned to ground ll6.
  • the general idea is to strobe or sequentially energize the respective anodes and at the same time activatethe appropriate associated cathode segments.
  • all anodes are initially de-energized, a condition which is obtained by holding the base of the transistors of the respective anode drivers 13a to l3n at a potential approximately equal to or slightly more posi tive than the B+ potential connected to the emitter of each anode driver.
  • Thereafteneach anode driver can be repetitively activated in sequence proceeding, for example, from the least to the most significant digits.
  • anode driver 13a in a first time interval t, of the repetition period T, the potential at the base of anode driver 13a is driven slightly negative with regard to its emitter to switch the transistor into an on or saturated state as indicated by the waveform of FIG. 2a and thereby connect the B+ supply directly to the anode of tube 10a.
  • anode driver 13b in time interval immediately following in terval t anode driver 13b is switched to an on condition as indicated inFIG. 2b to apply the B+ to the anodes of tube b and so on in succeeding time intervals until finally the 8+ is applied to tube lOn through anode driver l3n switched to an on condition in interval t,, as illustrated in FIG. 2c, after which the cycle repeats continuously for as long as it is desired to display the multi-digit number.
  • the corresponding cathodes a, b, c of the alternate cathode groups 12b through l2n are also activated, but this is of no consequence since the associated anodes are not energized during interval
  • all of the cathode driver elements of driver groups 14 and 14" and the odd and even-digit switches 15' and 15 may be assumed to be held initially in an off or deenergized condition.
  • the potential on the base of the transistor of odd-digit switch 15' is driven slightly-positive relative to ground to drive switch l5'into an on or satu rated state as illustrated in FIG.
  • cathode driver element 14a is not energied so that numeral 1 is displayed in the next to least significant digit position alongside numeral 7 in the least significant digit position.
  • the control signals applied to the base terminals of the cathode drivers are obtained from a conventional binary coded decimal to seven segment decoder 17 which receives four-wire input bits A, B, C, D in the standard format 0001, 0010, 0011, 0l00, etc., for the purpose of selecting the correct cathode segments to display any one of the numerals 0 to 9 in each digit position.
  • the decoder is synchronized with the on-off controlsignal applied to the anode drivers and the odd and even-digit switches by means of clock pulses obtained from timing control unit 18.
  • Units 17 and 18 may be an integral part of a system such as a calculator, clock or counter.
  • FIG. 3 An alternative cathode driver configuration which may be used in combination with the indicator tubes, anode drivers and timingcontrol unit of FIG. I is shown in FIG. 3.
  • This cathode driver configuration incorporates a latching feature which necessitates the use of a pair of binary coded decimal-to-seven-segment decoders 27', 27" coupled respectively to latching circuits 28 28''.
  • the circuit is thus more expensive than the one previously described, but offers the advantage of enhanced brightness in view of the fact that the cathode segmentsof each array may be held in an activated state for essentially the full duration of the respective timing intervals t, through 1,, rather than for only half of each interval. This will be understood more fully from a reading of the following description given with reference to FIGS.
  • each anode driver is switched on in succession as indicated in FIGS. 4a and 4b.
  • the B+ potential is coupled to tube 10a in time interval t
  • the least significant digit information (FIG. 4/) is applied to the pair of latch cicuits 28', 28" near the end of the preceding (n"') time interval.
  • the odddigit latch 28' is activated as by an odd-digit sample signal (FIG. 4c) supplied from the timing control'unit.
  • the least significant digit information is stored only in latch circuit 28.
  • an even-digit latch signal (FIG.
  • the general operating criteria for the driver configuration of the present invention is that a number of anode drivers equal to the number of'indicator tubes is required while the number of cathode driving elements required is equal to the number of cathode segments per tube with an additional switch being required for each group of cathode drivers. in the case of a three digit tube for example. a separate group of cathode drivers and a related group switch would be required for each digit position.
  • An electronic driver circuit for a gaseous cold cathode negative glow type display device including a plurality of groups of cathodes and a plurality of anodes wherein each anode is operatively associated with a group of cathodes and the individual cathodes of each group of cathodes are selectively activatable for displaying-desired characters by establishing a suitable potential difference between at least one cathode of each group and its associated anode, said circuit comprising cathode activating means including at least two groups of cathode activating elements, each group of cathode activating elements coupled to at least one distinct group of cathodes for selectively activating the cathodes thereof,
  • anode driver means coupled to said plurality of anodes for selectively applying electrical excitation in sequence. to respective groups of anodes each group including at least two anodes, and
  • control means coupled to said cathode activating means for successively and exclusively rendering said groups of cathode activating elements operable concurrently with each sequential energization of each of said groups of anodes so that a desired character is energized at the group of cathodes coupled to the currently operable group of cathodes activating elements and associated with the currently energized group of anodes.
  • said groups of cathode activating elements each include a plurality of individual cathode drivers each of which is coupled to a respective cathode of at least one group of cathodes.
  • a cold cathode negative glow type gaseous character display apparatus comprising means enclosing an ionizable gaseous medium
  • anode driver means coupled to said anodes for selectively applying electrical excitation in sequence to respective groups of anodes each group including at least two anodes,
  • cathode activating means including at least two groups of cathode activating elements, each group of cathode activating elements coupled to at least one distinct group of cathodes for selectively activating the cathodes thereof wherebydesired characters are displayed by establishing a suitable potential difference between at least one cathode of each group and its associated anode, and
  • control means coupled to said cathode activating means for sequentially and exclusively rendering said groups of cathode activating elements operable during application of electrical excitation to each group of anodes so that a desired character is energized at a different one of said groups of cathodes in successive time intervals at the group of cathodes coupled to the currently operable group of cathode activating elements and associated with the currently energized group of anodes.
  • said groups of cathode activating elements each include a plurality of individual cathode drivers each coupled-to a respective cathode of at least one group of cathodes.
  • the enclosing means comprises means forming a plurality of hermetically sealed tubes each including at least two groups of cathodes, one group of cathodes of each tube being connected to a first group of cathode activating elements and another group of cathodes of each tube being connected to a second group of cathode activating elements.
  • the enclosing means comprises means forming a plurality of hermetically sealed tubes each including a plurality of cathode groups, each cathode group of the respective tubes being connected toa discrete group of cathode activating elements.
  • each group of cathodes comprises an array of cathode segments arranged in an alphanumeric format whereby desired 1 characters are displayed by activating selected cathode segments of the respective groups of cathodes concurrently with application of electrical excitationto the associated anodes.
  • each group of anodes includes the same number of anodes, and the number of groups of cathode activating elements is equal in number to the number of anodes in each anode group.
  • the enclosing means comprises means forming a plurality of hermetically sealed tubes each including at least two groups of cathodes,'one group of cathodes of each tube being connected to a first group of cathode activating elements and another group of cathodes of each tube being connected to a second group of cathode activating elements.
  • each said group of anodes comprises adjacent anhermetically sealed tubes each including a plurality odes, and of cathode groups, each cathode group of the reeach said tube includes one respective group of anspective tubes being connected to a discrete group odes. of cathode activating elements, 5

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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)
US00269681A 1972-07-07 1972-07-07 Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits Expired - Lifetime US3815120A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
GB30633D GB30633A (de) 1972-07-07
US00269681A US3815120A (en) 1972-07-07 1972-07-07 Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits
CA172,774A CA977440A (en) 1972-07-07 1973-05-30 Gas discharge indicator time multiplex operated driver circuit
AU57308/73A AU466623B2 (en) 1972-07-07 1973-06-25 Gas discharge indicator time multiplex operated driver circuit
GB3063373A GB1399581A (en) 1972-07-07 1973-06-27 Character display system
IT51243/73A IT989747B (it) 1972-07-07 1973-07-04 Perfzionamento nei circuiti di pilotaggio per dispositivi di presentazione di dati
JP48076447A JPS4960135A (de) 1972-07-07 1973-07-06
DE19732334539 DE2334539A1 (de) 1972-07-07 1973-07-06 Treiberschaltungen fuer anzeigevorrichtungen
FR7324848A FR2192372B1 (de) 1972-07-07 1973-07-06
NL7309502A NL7309502A (de) 1972-07-07 1973-07-06
SE7309541A SE383662B (sv) 1972-07-07 1973-07-06 Elektronisk drivkrets for en gaspresentationsanordning

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00269681A US3815120A (en) 1972-07-07 1972-07-07 Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits

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US3815120A true US3815120A (en) 1974-06-04

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US00269681A Expired - Lifetime US3815120A (en) 1972-07-07 1972-07-07 Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits

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US (1) US3815120A (de)
JP (1) JPS4960135A (de)
AU (1) AU466623B2 (de)
CA (1) CA977440A (de)
DE (1) DE2334539A1 (de)
FR (1) FR2192372B1 (de)
GB (2) GB1399581A (de)
IT (1) IT989747B (de)
NL (1) NL7309502A (de)
SE (1) SE383662B (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3918041A (en) * 1974-08-05 1975-11-04 Roger A Mao Multiplex display system
US4242615A (en) * 1979-02-14 1980-12-30 Beckman Instruments, Inc. Gas discharge tube driver and level shifter circuit
US4266224A (en) * 1979-02-26 1981-05-05 Beckman Instruments, Inc. High performance information display panel
WO1981001476A1 (en) * 1979-11-19 1981-05-28 Ncr Co Display control circuit
DE3044923A1 (de) * 1979-11-29 1981-09-24 Beckman Instruments Inc., 92634 Fullerton, Calif. "anzeige- bzw. wiedergabesystem"
US4307394A (en) * 1980-05-12 1981-12-22 Sangamo Weston, Inc. System for driving a gas discharge display
US4542379A (en) * 1979-11-29 1985-09-17 Tokyo Shibaura Denki Kabushiki Kaisha Circuit for driving a display device

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4988434A (de) * 1972-12-25 1974-08-23
JPS51829U (de) * 1974-06-18 1976-01-06
JPS60160727A (ja) * 1984-02-01 1985-08-22 Hitachi Micro Comput Eng Ltd 直並列変換回路およびこれを用いた表示駆動装置

Citations (6)

* 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
US3354342A (en) * 1964-02-24 1967-11-21 Burroughs Corp Solid state sub-miniature display apparatus
US3395268A (en) * 1965-06-10 1968-07-30 Monsanto Co Blanking circuit for a plural cathode display tube
US3555544A (en) * 1968-11-18 1971-01-12 Wagner Electric Corp Time-sharing indicator lamp control circuit
US3614771A (en) * 1969-09-18 1971-10-19 Hewlett Packard Co Display apparatus
US3679933A (en) * 1968-12-23 1972-07-25 Sony Corp Display system

Patent Citations (6)

* 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
US3354342A (en) * 1964-02-24 1967-11-21 Burroughs Corp Solid state sub-miniature display apparatus
US3395268A (en) * 1965-06-10 1968-07-30 Monsanto Co Blanking circuit for a plural cathode display tube
US3555544A (en) * 1968-11-18 1971-01-12 Wagner Electric Corp Time-sharing indicator lamp control circuit
US3679933A (en) * 1968-12-23 1972-07-25 Sony Corp Display system
US3614771A (en) * 1969-09-18 1971-10-19 Hewlett Packard Co Display apparatus

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3918041A (en) * 1974-08-05 1975-11-04 Roger A Mao Multiplex display system
US4242615A (en) * 1979-02-14 1980-12-30 Beckman Instruments, Inc. Gas discharge tube driver and level shifter circuit
US4266224A (en) * 1979-02-26 1981-05-05 Beckman Instruments, Inc. High performance information display panel
WO1981001476A1 (en) * 1979-11-19 1981-05-28 Ncr Co Display control circuit
DE3044923A1 (de) * 1979-11-29 1981-09-24 Beckman Instruments Inc., 92634 Fullerton, Calif. "anzeige- bzw. wiedergabesystem"
US4542379A (en) * 1979-11-29 1985-09-17 Tokyo Shibaura Denki Kabushiki Kaisha Circuit for driving a display device
US4307394A (en) * 1980-05-12 1981-12-22 Sangamo Weston, Inc. System for driving a gas discharge display

Also Published As

Publication number Publication date
CA977440A (en) 1975-11-04
AU5730873A (en) 1975-01-09
NL7309502A (de) 1974-01-09
JPS4960135A (de) 1974-06-11
IT989747B (it) 1975-06-10
FR2192372B1 (de) 1978-07-21
GB1399581A (en) 1975-07-02
DE2334539A1 (de) 1974-01-24
GB30633A (de)
FR2192372A1 (de) 1974-02-08
SE383662B (sv) 1976-03-22
AU466623B2 (en) 1975-11-06

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